0001564590-22-013023 | 10-K | XBRL Viewer

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Fair Value of Financial Instruments - Summary of Changes in Fair Value of Level 3 Financial Instruments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Purchase price contingent liability [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at the beginning of period	$ 10,278	$ 5,938
Change in value of liabilities		4,340
Change in value of contingent liability due to estimated future revenue milestones	3,249
Change in value of contingent liability due to assignment of rights to Soleno	(3,980)
Balance at end of period	9,547	$ 10,278
Series C Warrant [Member] \| Common stock warrant liability [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at the beginning of period, in shares		118,083
Expiration of warrants, in shares		(118,083)
2017 PIPE Warrant Liability [Member] \| Common stock warrant liability [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at the beginning of period		$ 10,822
Balance at the beginning of period, in shares		6,024,425
Expiration of warrants, in shares		(6,024,425)
Expiration of warrants		$ (10,822)
2018 PIPE Warrant Liability [Member] \| Common stock warrant liability [Member]
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at the beginning of period	$ 539	$ 1,354
Balance at the beginning of period, in shares	513,617	513,617
Change in value of liabilities	$ (508)	$ (815)
Balance at end of period	$ 31	$ 539
Balance at the end of period, in shares	513,617	513,617

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Summary of Significant Accounting Policies

Note 3. Summary of Significant Accounting Policies

Basis of Presentation

The accompanying consolidated financial statements have been prepared on a going concern basis in accordance with accounting principles generally accepted in the United States of America (GAAP), and the applicable rules and regulations of the Securities and Exchange Commission (SEC).

The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.

Use of Estimates

The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities, and reported amounts of expenses in the financial statements and accompanying notes. Actual results could differ from those estimates. Key estimates included in the financial statements include the valuation of deferred income tax assets, the valuation of financial instruments, stock-based compensation, accrued costs for services rendered in connection with third-party contactor clinical trial activities, and the valuation of contingent liabilities for the purchase price of assets obtained through acquisition.

Concentration of Credit Risk

Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash and cash equivalents at one U.S. commercial bank. Cash and cash equivalents deposited with this commercial bank exceeded the Federal Deposit Insurance Corporation insurable limit at December 31, 2021 and 2020. The Company expects the maintenance of balances in excess of insurable limits will continue.

Segments

The Company operates in one segment. Management uses one measurement of profitability and does not segregate its business for internal reporting, making operating decisions, and assessing financial performance. All long-lived assets are maintained in the U.S.

Cash and Cash Equivalents

The Company considers all highly liquid investments, including its money market fund, purchased with an original maturity of three months or less to be cash equivalents. The Company’s cash and cash equivalents are held in institutions in the U.S., the U.K. and Ireland and include deposits in a money market fund which was unrestricted as to withdrawal or use.

Prepaid Expenses and Other Current Assets

Prepaid expenses and other current assets consist of payments primarily related to clinical trials, insurance and short-term deposits. Prepaid expenses are initially recorded upon payment and are expensed as goods or services are received.

Property and Equipment, Net

Property and equipment are stated at cost net of accumulated depreciation and amortization calculated using the straight-line method over the estimated useful lives of the assets, generally between three and five years. Leasehold improvements are amortized on a straight-line basis over the lesser of their useful life or the remaining term of the lease. Maintenance and repairs are charged to expense as incurred, and improvements are capitalized. When assets are retired or otherwise disposed of, the cost and accumulated depreciation are removed from the balance sheet and any resulting gain or loss is reflected in operations in the period realized.

Leases

The Company determines whether an arrangement is a lease at inception. Specifically, it considers whether it controls the underlying asset and has the right to obtain substantially all the economic benefits or outputs from the asset. If the contractual arrangement contains a lease, the Company then determines whether it is an operating or finance lease. Right-of-Use (ROU) assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. ROU assets and lease liabilities are recognized at commencement date based on the present value of lease payments over the lease term. Lease expense for operating lease payments is recognized on a straight-line basis over the lease term. Finance lease classification results in a front-loaded expense recognition pattern over the lease term as it recognizes interest expense and amortization expense as separate components of lease expense.

The Company does not separate lease components from non-lease components for all classes of underlying assets, and instead accounts for the lease and non-lease components as a single component. Variable lease payments are recognized as they are incurred and primarily include common area maintenance, utilities, real estate taxes, insurance and other operating costs that are passed on from the lessor in proportion to the space leased by the Company. The Company does not recognize lease assets and lease liabilities for leases with an original lease term of less than one year.

Long-Lived Assets

The Company reviews its long-lived assets for impairment annually and whenever events or changes in circumstances indicate that the carrying amount of the assets may not be fully recoverable. The Company evaluates assets for potential impairment by comparing estimated future undiscounted net cash flows to the carrying amount of the asset. If the carrying amount of the assets exceeds the estimated future undiscounted cash flows, impairment is measured based on the difference between the carrying amount and the fair value of the assets.

Intangible Assets

In March 2017, the Company completed the acquisition of Essentialis in accordance with the merger agreement by and between the Company Soleno Therapeutics and Essentialis dated December 22, 2016 (the “Merger Agreement”). The merger transaction was accounted for as an asset acquisition under the acquisition method of accounting and accordingly, the value of $22.0 million was assigned to the identifiable intangible asset relating to the patent for DCCR, which patent expires in June 2028.

Intangible assets with finite lives are amortized on a straight-line basis over their estimated useful lives, which for the patent is 11 years. The useful life of the intangible asset is evaluated each reporting period to determine whether events and circumstances warrant a revision to the remaining useful life.

Research and Development

Research and development costs are charged to operations as incurred. Research and development costs consist primarily of salaries, benefits, bonus, share-based compensation, consultant fees, certain facility costs and other costs associated with clinical trials. Clinical trial costs are a significant component of research and development expenses and include costs associated with third-party contractors and other vendors. Invoicing from third-party contractors for services performed can often occur several months later. The Company accrues the costs incurred for clinical trial activities as measured by patient progression and the timing of various aspects of the trial. For other services the Company accrues the costs in connection with third-party contractor activities based on its estimate of fees and costs associate with the contract that were rendered during the period and they are expensed as incurred.

Costs to acquire technologies to be used in research and development that have not reached technological feasibility and have no alternative future use are expensed to research and development costs when incurred.

Change in fair value of contingent consideration

The Company recorded the value of contingent future consideration to be paid for the acquisition of Essentialis as a liability in March 2017 at the date of the acquisition. The changes in value of the liability for the

contingent consideration since the acquisition date are recorded as operating expense in the consolidated statements of operations.

Income Taxes

The Company accounts for income taxes using the asset and liability method. Under this method, deferred income tax assets and liabilities are recorded based on the estimated future tax effects of differences between the amounts at which assets and liabilities are recorded for financial reporting purposes and the amounts recorded for income tax purposes. A valuation allowance is provided against the Company’s deferred income tax assets when their realization is not reasonably assured.

The Company assesses all material positions taken in any income tax return, including all significant uncertain positions, in all tax years that are still subject to assessment or challenge by relevant taxing authorities. Assessing an uncertain tax position begins with the initial determination of the position’s sustainability and is measured at the largest amount of benefit that is greater than fifty percent likely of being realized upon ultimate settlement. As of each balance sheet date, unresolved uncertain tax positions must be reassessed, and the Company will determine whether (i) the factors underlying the sustainability assertion have changed and (ii) the amount of the recognized tax benefit is still appropriate. The recognition and measurement of tax benefits requires significant judgment. Judgments concerning the recognition and measurement of a tax benefit might change as new information becomes available.

Common Stock Purchase Warrants and Other Derivative Financial Instruments

The Company classifies common stock purchase warrants and other free standing derivative financial instruments as equity if the contracts (i) require physical settlement or net-share settlement or (ii) give the Company a choice of net-cash settlement or settlement in its own shares (physical settlement or net-share settlement). The Company classifies any contracts that (i) require net-cash settlement (including a requirement to net cash settle the contract if an event occurs and if that event is outside the control of the Company), (ii) give the counterparty a choice of net-cash settlement or settlement in shares (physical settlement or net-share settlement), or (iii) contain reset provisions as either an asset or a liability. The Company assesses classification of its freestanding derivatives at each reporting date to determine whether a change in classification between equity and liabilities is required. The Company determined that certain freestanding derivatives, which principally consist of Series C, the 2017 PIPE Warrants and 2018 PIPE Warrants, do not satisfy the criteria for classification as equity instruments due to the existence of certain cash settlement features that are not within the sole control of the Company or variable settlement provision that cause them to not be indexed to the Company’s own stock.

Stock-Based Compensation

Stock-based compensation costs related to stock options and restricted stock units granted to employees, nonemployees and directors are measured at the date of grant based on the estimated fair value of the award. For restricted stock units this fair value is based on the Company’s common stock price on the grant date. The Company estimates the grant date fair value of stock options, and the resulting stock-based compensation expense, using the Black-Scholes option-pricing model. The grant date fair value of stock-based awards is recognized on a straight-line basis over the requisite service period, which is generally the vesting period for service-based awards. For performance-based awards the requisite service period is the longest explicit, implicit or derived service period based on management’s estimate of the probability of the performance criteria being satisfied, adjusted at each balance sheet date.

The Black-Scholes option-pricing model requires the use of highly subjective assumptions to estimate the fair value of stock-based awards. If the Company had made different assumptions, its stock-based compensation expense, net loss and net loss per share of common stock could have been significantly different. These assumptions include:

•

Expected volatility: The Company calculated the estimated volatility rate used to value stock options granted during 2021 based on the volatility of its common stock for a historical period equal to the expected life of the stock options. For stock options granted during 2020, and prior to having sufficient

history of the Company’s common stock volatility, the estimated volatility rate was based on the volatility of the Company’s common stock together with comparable companies in its industry.

•

Expected life: Due to the lack of historical exercise history, the expected life of the Company’s service-based stock options is determined utilizing the “simplified method”, based on the average of the contractual term of the options and the weighted-average vesting period. The expected life for performance-based options is determined based on consideration of the contractual term of the stock options, an estimate of the date the performance criteria would be met and expectations of employee behavior.

•

Risk-free rate: The risk-free interest rate is based on the yields of U.S. Treasury securities with maturities similar to the expected time to liquidity.

•

Expected divided yield: The Company has never declared or paid any cash dividends and do not presently plan to pay cash dividends in the foreseeable future. Consequently, it used an expected dividend yield of zero.

The Company accounts for forfeitures as they occur.

Recent Accounting Standards

Recently Adopted Accounting Standards

In December 2019, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) No. 2019-12: “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes”, related to simplifying the accounting for income taxes. The guidance eliminates certain exceptions from Accounting Standards Codification (ASC) 740 related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. The guidance also clarifies and simplifies other aspects of the accounting for income taxes. The guidance became effective for the Company beginning in the first quarter of 2021 on a prospective basis. The Company adopted this standard on January 1, 2021, and it did not have a material impact on the Company’s consolidated financial statements or the related disclosures.

Recently Issued Accounting Standards

During the year ended December 31, 2021, there have been no new, or existing recently issued, accounting pronouncements that are of significance, or potential significance, that impact the Company’s consolidated financial statements.

Consolidated Statements of Stockholders' Equity (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($)
Statement Of Stockholders Equity [Abstract]
Less transaction costs	$ 3,778

Stockholders' Equity (Tables)

12 Months Ended

Dec. 31, 2021

Equity [Abstract]

Summary of Stock Based Compensation Expense

Stock compensation expense was allocated between departments as follows (in thousands).

	Year ended
	December 31, 2021		December 31, 2020
Research and development	$	734	$	348
General and administrative		2,542		1,152
Total	$	3,276	$	1,500

Schedule of Fair Value of Award Granted Using Black-Scholes Option Pricing Model

Of the total options granted during the year ended December 31, 2021, 708,750 were performance-based options. The fair value of each award granted was estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions.

	Year Ended
	December 31, 2021	December 31, 2020
Expected life (years)	5.5-6.0	5.5-6.1
Risk-free interest rate	0.6%-1.4%	0.4%-0.5%
Volatility	89%-108%	64%-96%
Weighted average volatility	104%	78%
Dividend rate	— %	— %

Summary of Stock Option and Restricted Stock Unit Transactions

The following table summarizes stock option and restricted stock unit transactions for the years ended December 31, 2021 and 2020 as issued under the 2014 Plan and the Inducement Plan.

	Number of Options			Weighted- Average Exercise Price per		Weighted Average Remaining Contractual Term		Aggregate Intrinsic Value
	Outstanding			Share		(in years)		(in thousands)
Balance at December 1, 2020		2,123,117		$	4.62		7.87
Options granted		824,150		$	2.79
Options exercised		(8,518	)	$	1.96
Options canceled/forfeited		(101,010	)	$	2.34
Balance at December 31, 2020		2,837,739		$	4.18		7.62
Options granted		3,462,810		$	2.13
Options canceled/forfeited		(175,000	)	$	1.91
Balance at December 31, 2021		6,125,549		$	3.09		7.94	$	—
Options exercisable at December 31, 2021		2,814,405		$	4.15		6.81	$	—
Options vested and expected to vest at December 31, 2021		5,781,174		$	3.14		7.88	$	—

Summary of Restricted Stock Unit Transactions

The following table summarizes restricted stock unit transactions for the years ended December 31, 2021 and 2020 as issued under the 2014 Plan:

	Number of Restricted Stock Units			Weighted- Average Grant-Date Fair Value per Share
Outstanding at January 1, 2020		—
Restricted stock units granted		751,633		$	3.68
Restricted stock units vested		(103,133	)	$	2.60
Restricted stock units cancelled		(67,500	)	$	3.85
Outstanding at December 31, 2020		581,000		$	3.85
Restricted stock units granted		177,941		$	1.05
Restricted stock units vested		(323,191	)	$	2.31
Outstanding at December 31, 2021		435,750		$	3.85

Other Financial Statements Details - Intangible Assets (Detail) - Patents and Merger Costs [Member] - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Finite Lived Intangible Assets [Line Items]
Amount	$ 22,003	$ 22,003
Accumulated Amortization	(9,366)	(7,422)
Net Amount	$ 12,637	$ 14,581

Overview

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Overview

Note 1. Overview

Soleno Therapeutics, Inc. (the Company or Soleno) is focused on the development and commercialization of novel therapeutics for the treatment of rare diseases. Its lead candidate is Diazoxide Choline Extended Release tablets (DCCR), a once-daily oral tablet for the treatment of Prader-Willi Syndrome (PWS). DCCR has received orphan designation for the treatment of PWS in the United States (U.S.) as well as in the European Union (E.U.).

The Company incorporated in the State of Delaware on August 25, 1999, and is located in Redwood City, California. It initially established its operations as Capnia, a diversified healthcare company that developed and commercialized innovative diagnostics, devices and therapeutics addressing unmet medical needs. During 2017, the Company merged with Essentialis, Inc (Essentialis) and subsequently received stockholder approval to amend its Amended and Restated Certificate of Incorporation to change its name from “Capnia, Inc.” to “Soleno Therapeutics, Inc.” Essentialis was a privately held clinical-stage company focused on the development of breakthrough medicines for the treatment of rare diseases where there is increased mortality and risk of cardiovascular and endocrine complications. After the merger, the Company’s primary focus has been the development and commercialization of novel therapeutics for the treatment of rare diseases and the Company divested all prior business efforts.

Income Taxes - Schedule of Geographical Distribution of Loss before Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Abstract]
United States	$ (30,453)	$ (22,197)
Foreign	(457)	(2,442)
Loss before income taxes	$ (30,910)	$ (24,639)

- Definition

Amount of income (loss) from continuing operations, including income (loss) from equity method investments, before deduction of income tax expense (benefit), and income (loss) attributable to noncontrolling interest.

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+ Details

Other Financial Statement Details - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Other Financial Statement Details Disclosure [Abstract]
Depreciation expense	$ 19,000	$ 11,000
Amortization	$ 1,900,000	$ 1,900,000

Stockholders' Equity - Schedule of Fair Value of Award Granted Using Black-Scholes Option Pricing Model (Detail)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average volatility	104.00%	78.00%
Dividend rate	0.00%	0.00%
Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected life (years)	5 years 6 months	5 years 6 months
Risk-free interest rate	0.60%	0.40%
Volatility	89.00%	64.00%
Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected life (years)	6 years	6 years 1 month 6 days
Risk-free interest rate	1.40%	0.50%
Volatility	108.00%	96.00%

Income Taxes - Summary of Gross Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Reconciliation Of Unrecognized Tax Benefits Excluding Amounts Pertaining To Examined Tax Returns Roll Forward
Beginning balance	$ 1,323	$ 1,111
Decrease related to prior year tax positions		(4)
Increase related to current year tax positions	234	216
Ending balance	$ 1,557	$ 1,323

Commitments and Contingencies

12 Months Ended

Dec. 31, 2021

Commitments And Contingencies Disclosure [Abstract]

Commitments and Contingencies

Note 8. Commitments and Contingencies

In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and provide for general indemnifications. The Company’s exposure under these agreements is unknown because it involves claims that may be made against the Company in the future but have not yet been made. The Company accrues a liability for such matters when it is probable that future expenditures will be made, and such expenditures can be reasonably estimated.

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Current assets
Cash and cash equivalents	$ 21,304	$ 49,224
Prepaid expenses and other current assets	1,118	1,019
Total current assets	22,422	50,243
Long-term assets
Property and equipment, net	33	19
Operating lease right-of-use assets	421	124
Finance lease right-of-use assets		15
Intangible assets, net	12,637	14,581
Other long-term assets	40
Total assets	35,553	64,982
Current liabilities
Accounts payable	3,254	3,489
Accrued compensation	728	1,005
Accrued clinical trial site costs	3,420	3,789
Operating lease liabilities	282	139
Other current liabilities	323	196
Total current liabilities	8,007	8,618
Long-term liabilities
Contingent liability for Essentialis purchase price	9,547	10,278
Long-term lease liabilities	175	0
Total liabilities	17,760	19,435
Commitments and contingencies (Note 8)
Stockholders’ equity
Common stock, $0.001 par value, 250,000,000 shares authorized, 79,864,310 and 79,615,692 shares issued and outstanding at December 31, 2021 and December 31, 2020, respectively.	80	80
Additional paid-in-capital	231,068	227,912
Accumulated deficit	(213,355)	(182,445)
Total stockholders’ equity	17,793	45,547
Total liabilities and stockholders’ equity	35,553	64,982
2018 PIPE Warrant Liability [Member]
Long-term liabilities
Warrant liability	$ 31	$ 539

Warrant Liabilities (Tables)

12 Months Ended

Dec. 31, 2021

2018 PIPE Warrant Liability [Member]

Fair Value of Convertible Preferred Stock Warrant Liability

The following summarizes certain key assumptions used in estimating the fair values.

	December 31, 2021			December 31, 2020
Volatility		95	%		88	%
Contractual term (years)		2.0			3.0
Expected dividend yield		—	%		—	%
Risk-free rate		0.72	%		0.17	%

Going Concern and Management's Plans - Additional Information (Detail) - USD ($) $ in Thousands		12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash And Cash Equivalents [Line Items]
Net loss		$ 30,910	$ 24,639
Accumulated deficit		213,355	182,445
Cash and cash equivalents		21,304	49,224
Net cash used in operating activities		$ 27,770	$ 25,224
Underwritten Public Offering [Member]
Cash And Cash Equivalents [Line Items]
Proceeds from sale of common stock, net of costs	$ 13,900

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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+ Details

- Definition

The cumulative amount of the reporting entity's undistributed earnings or deficit.

+ References + Details

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	79,864,310	79,615,692
Common stock, shares outstanding	79,864,310	79,615,692

Income Taxes - Provision for Income Tax Benefit by Applying Statutory Federal Income Tax Rate to Operating Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Expense Benefit Continuing Operations Income Tax Reconciliation [Abstract]
Tax (benefit) on the loss before income tax expense computed at the federal statutory rate	$ (6,501)	$ (5,174)
State tax (benefit) at statutory rate, net of federal benefit	(2,342)	(2,293)
Foreign rate differential	12	51
Change in valuation allowance	8,711	8,231
Change in research and development credits	(364)	(303)
Stock based compensation—ISOs	52	71
Change in fair value of warrants	(107)	(2,444)
Change in fair value of contingent consideration	(153)	911
Change in net operating loss true up	712	846
Other	$ (20)	$ 104

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating expenses
Research and development	$ 21,453	$ 23,191
General and administrative	10,806	8,758
Change in fair value of contingent consideration	(731)	4,340
Total operating expenses	31,528	36,289
Operating loss	(31,528)	(36,289)
Other income
Change in fair value of warrants liabilities	508	11,637
Interest income	110	13
Total other income	618	11,650
Net loss	$ (30,910)	$ (24,639)
Loss per common share, basic and diluted	$ (0.39)	$ (0.39)
Weighted-average common shares outstanding used to calculate basic and diluted net loss per common share	79,770,334	62,620,227

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2021

Accounting Policies [Abstract]

Basis of Presentation

The consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All intercompany transactions and balances have been eliminated in consolidation.

Use of Estimates

Concentration of Credit Risk

Segments

Cash and Cash Equivalents

Prepaid Expenses and Other Current Assets

Property and Equipment, Net

Leases

Long-Lived Assets

Intangible Assets

Research and Development

Change in Fair Value of Contingent Consideration

Change in fair value of contingent consideration

contingent consideration since the acquisition date are recorded as operating expense in the consolidated statements of operations.

Income Taxes

Common Stock Purchase Warrants and Other Derivative Financial Instruments

Stock-Based Compensation

•

history of the Company’s common stock volatility, the estimated volatility rate was based on the volatility of the Company’s common stock together with comparable companies in its industry.

•

Risk-free rate: The risk-free interest rate is based on the yields of U.S. Treasury securities with maturities similar to the expected time to liquidity.

•

The Company accounts for forfeitures as they occur.

Recent Accounting Standards

Recently Adopted Accounting Standards

Recently Issued Accounting Standards

Stockholders' Equity - Summary of Restricted Stock Unit Transactions (Detail) - Restricted Stock Units [Member] - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Restricted stock units granted	177,941	751,633
Weighted-average grant date fair value
Restricted stock units granted (in dollars per share)	$ 700,000	$ 300,000
2014 Equity Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Beginning balance	581,000
Restricted stock units granted	177,941	751,633
Restricted stock units vested	(323,191)	(103,133)
Restricted stock units cancelled		(67,500)
Ending balance	435,750	581,000
Weighted-average grant date fair value
Beginning balance (in dollars per share)	$ 3.85
Restricted stock units granted (in dollars per share)	1.05	$ 3.68
Restricted stock units vested (in dollars per share)	2.31	2.60
Restricted stock units cancelled (in dollars per share)		3.85
Ending balance (in dollars per share)	$ 3.85	$ 3.85

Leases - Schedule of Supplemental Cash Flow Information Related to Leases (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$ 277	$ 336
Operating cash flows from finance leases		2
Financing cash flows from finance leases	$ 8	$ 17

Fair Value of Financial Instruments

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Fair Value of Financial Instruments

Note 4. Fair Value of Financial Instruments

The carrying value of the Company’s cash, cash equivalents and accounts payable, approximate fair value due to the short-term nature of these items.

Fair value is defined as the exchange price that would be received for an asset or an exit price paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs.

The fair value hierarchy defines a three-level valuation hierarchy for disclosure of fair value measurements as follows:

•

Level I — Unadjusted quoted prices in active markets for identical assets or liabilities;

•

Level II — Inputs other than quoted prices included within Level I that are observable, unadjusted quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities; and

•

Level III — Unobservable inputs that are supported by little or no market activity for the related assets or liabilities.

The categorization of a financial instrument within the valuation hierarchy is based upon the lowest level of input that is significant to the fair value measurement.

The following table sets forth the Company’s financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands).

	Fair Value Measurements at December 31, 2021
	Total		Level 1		Level 2		Level 3
Liabilities
2018 PIPE warrant liability	$	31	$	—	$	—	$	31
Essentialis purchase price contingency liability		9,547		—		—		9,547
Total common stock warrant and contingent consideration liability	$	9,578	$	—	$	—	$	9,578

	Fair Value Measurements at December 31, 2020
	Total		Level 1		Level 2		Level 3
Liabilities
2018 PIPE warrant liability	$	539	$	—	$	—	$	539
Essentialis purchase price contingency liability		10,278		—		—		10,278
Total common stock warrant and contingent consideration liability	$	10,817	$	—	$	—	$	10,817

The Company’s estimated fair value of the 2018 PIPE Warrants was calculated using a Black-Scholes pricing model. The Black-Scholes pricing model requires the input of highly subjective assumptions including the expected stock price volatility, the expected term, the expected dividend yield and the risk-free interest rate.

Based on the terms of the Company’s completed merger with Essentialis on March 7, 2017, it was obligated to make cash earnout payments of up to a maximum of $30.0 million to the former Essentialis stockholders. On December 28, 2021, in connection with the dissolution of two of the former Essentialis stockholders, the two former stockholders entered into an agreement with the Company which assigned the right, title and interest to all their future earnout payments to the Company. As a result of the assignment, as of December 31, 2021, and going forward, the maximum cash earnout payments are $21.2 million. The fair value of the Essentialis purchase price contingent liability is estimated using scenario-based methods based upon the Company’s analysis of the likelihood of obtaining specified approvals from the Federal Drug Administration as well as reaching cumulative revenue milestones. The Level 3 estimates are based, in part, on subjective assumptions. In determining the likelihood of this occurring, the analysis relied on published research relating to clinical development success rates. Based on management’s assessment, a 72% and 67% probability of achieving each milestone was determined to be reasonable as of December 31, 2021 and December 31, 2020, respectively. Additionally, as of December 31, 2021, the Company anticipated that it could reach the commercial milestones of $100.0 million and $200.0 million in applicable revenue by the end 2024 and 2025, respectively. As of December 31, 2020, the Company anticipated that it would reach the same commercial milestones in applicable revenue by the middle of 2024 and 2026, respectively. During the periods presented, the Company has not changed the manner in which it values its Essentialis purchase price contingent liability.

The Company recognizes transfers between levels of the fair value hierarchy as of the end of the reporting period. There were no transfers within the hierarchy during the periods presented.

The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 liabilities (dollars in thousands).

	Series C Warrants					2017 PIPE Warrants						2018 PIPE Warrants					Purchase Price
	Number of					Number of						Number of					Contingent
	Warrants			Liability		Warrants			Liability			Warrants		Liability			Liability
Balance at January 1, 2020		118,083		$	—		6,024,425		$	10,822			513,617	$	1,354		$	5,938
Expiration of Series C Warrants		(118,083	)		—		—			—			—		—			—
Expiration of 2017 PIPE Warrants		—			—		(6,024,425	)		(10,822	)		—		—			—
Change in value of 2018 PIPE Warrants		—			—		—			—			—		(815	)		—
Change in value of contingent liability		—			—		—			—			—		—			4,340
Balance at December 31, 2020		—			—		—			—			513,617		539			10,278
Change in value of 2018 PIPE Warrants		—			—		—			—			—		(508	)		—
Change in value of contingent liability due to estimated future revenue milestones		—			—		—			—			—		—			3,249
Change in value of contingent liability due to assignment of rights to Soleno		—			—		—			—			—		—			(3,980	)
Balance at December 31, 2021		—		$	—		—		$	—			513,617	$	31		$	9,547

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Net loss per share - Schedule of Potentially Dilutive Securities Outstanding Excluded from Computations of Diluted Weighted-Average Shares Outstanding (Detail) - shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computations of diluted weighted-average shares outstanding	7,193,486	4,050,926
Warrants Issued to 2010/2012 Convertible Note Holders to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computations of diluted weighted-average shares outstanding	102,070	102,070
Options to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computations of diluted weighted-average shares outstanding	6,125,549	2,837,739
Outstanding Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computations of diluted weighted-average shares outstanding	435,750	581,000
Warrants Issued to Underwriter to Purchase Common Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computations of diluted weighted-average shares outstanding	16,500	16,500
2018 PIPE Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computations of diluted weighted-average shares outstanding	513,617	513,617

Income Taxes

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Income Taxes

Note 11. Income Taxes

The geographical distribution of loss before income taxes are summarized below (in thousands).

	December 31,
	2021			2020
United States	$	(30,453	)	$	(22,197	)
Foreign		(457	)		(2,442	)
Loss before income taxes	$	(30,910	)	$	(24,639	)

The provision for income tax benefit differs from the amount estimated by applying the statutory federal income tax rate to the operating loss due to the following (in thousands).

	December 31,
	2021			2020
Tax (benefit) on the loss before income tax expense computed at the federal statutory rate	$	(6,501	)	$	(5,174	)
State tax (benefit) at statutory rate, net of federal benefit		(2,342	)		(2,293	)
Foreign rate differential		12			51
Change in valuation allowance		8,711			8,231
Change in research and development credits		(364	)		(303	)
Stock based compensation—ISOs		52			71
Change in fair value of warrants		(107	)		(2,444	)
Change in fair value of contingent consideration		(153	)		911
Change in net operating loss true up		712			846
Other		(20	)		104
Provision for income tax benefit	$	—		$	—

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of the Company’s deferred tax assets and liabilities are as follows at December 31, 2021 and 2020 (in thousands).

	December 31,
	2021			2020
Non-current deferred tax assets:
Federal and state net operating loss carryforwards	$	48,542		$	41,999
Research and other credits		3,312			2,803
Reserves and accruals		573			236
Fixed assets		59			63
Capital loss carryover		1,115			1,115
Stock based compensation		1,133			337
Lease liability		133			41
Other deferred tax assets		102			129
Gross non-current deferred tax assets		54,969			46,723
Intangible assets		(3,536	)		(4,080	)
Right-of-use assets		(118	)		(39	)
Total non-current deferred tax liabilities		(3,654	)		(4,119	)
Total deferred tax assets		51,315			42,604
Valuation allowance		(51,315	)		(42,604	)
Net deferred tax assets	$	—		$	—

The Company has recorded a full valuation allowance against its net deferred tax assets due to the uncertainty as to whether such assets will be realized. The valuation allowance increased by $8.7 million from December 31, 2020 to December 31, 2021 primarily due to the generation of current year net operating losses and research and development credits claimed.

As of December 31, 2021, the Company had $189.3 million of federal, $116.4 million of state and $2.5 million of foreign net operating losses available to offset future taxable income. The Federal net operating loss carryforwards arising from years prior to 2018 began to expire in 2021, however post 2017 federal net operating loss carryforwards of $82.9 million may be carried forward indefinitely. The state net operating loss carryforwards will begin to expire in 2028 and the foreign net operating loss carryforward can be carried forward indefinitely, if not utilized. As of December 31, 2021, the Company also had $2.1 million of federal and $1.2 million of state research and development credit carryforwards. The federal research and development credit carryforward begin to expire in 2024 and the state research and development credit can be carried forward indefinitely.

Utilization of the net operating loss and tax credit carry forwards are subject to an annual limitation due to the ownership percentage change limitations provided by the Internal Revenue Code of 1986 and similar state provisions. The annual limitation may result in the expiration of the net operating loss before utilization. The Company completed Section 382 analysis through December 2016 and determined that an ownership change, as defined under Section 382 of the Internal Revenue Code, occurred in June 2016. The Company’s tax attributes are subject to an annual limitation of $0.5 million per year for federal purposes. For years ended after December 31, 2016, the utilization of net operating losses and tax credit carryforwards are subject to further limitation in the event an additional ownership change were to occur for tax purposes. The Company is currently in the process of analyzing whether there was an ownership change, as defined under Section 382 of the Internal Revenue Code, resulting from the issuance of new shares during 2018 through 2021 and expects that analysis to completed during 2022. As such, as of the date of these consolidated financial statements the Company is not able to determine the impact on the net operating loss (NOL) carryforwards, if any.

U.S. taxes and foreign withholding taxes have not been provided on undistributed earnings for certain non-U.S. subsidiaries as of December 31, 2021, as the earnings, if any, are intended to be indefinitely reinvested.

The following tables summarize the activities of gross unrecognized tax benefits (in thousands).

	December 31,
	2021		2020
Beginning balance	$	1,323	$	1,111
Decrease related to prior year tax positions		—		(4	)
Increase related to current year tax positions		234		216
Ending balance	$	1,557	$	1,323

The Company uses the “more likely than not” criterion for recognizing the tax benefit of uncertain tax positions and to establish measurement criteria for income tax benefits. The Company has determined it has $1.6 million of unrecognized assets and liabilities related to uncertain tax positions as of December 31, 2021. Changes in the unrecognized tax benefits within the next 12 months are expected to be similar to prior years and should not significantly increase or decrease. In the event the Company should need to recognize interest and penalties related to unrecognized tax liabilities, this amount will be recorded as a component of other expense.

There were no unrecognized tax benefits that would impact the effective tax rate as of December 31, 2021 and December 31, 2020. As of December 31, 2021, unrecognized tax benefits of $1.6 million would be offset by a change in valuation allowance.

The Company files income tax returns in the U.S. federal jurisdiction, certain state jurisdictions, United Kingdom and Ireland. In the normal course of business, the Company is subject to examination by federal, state, local and foreign jurisdictions, where applicable. In the U.S federal jurisdiction, tax years 1999 forward remain open to examination, in the state tax jurisdiction, years 2008 forward remain open to examination and in the foreign jurisdiction, years 2015 forward remain open to examination. The Company is currently not under audit by any federal, state, local or foreign jurisdiction.

The Coronavirus Aid, Relief, and Economic Security (CARES) Act, was enacted March 27, 2020. Among the business provisions, the CARES Act provided for various payroll tax incentives, changes to net operating loss carryback and carryforward rules, business interest expense limitation increases, and bonus depreciation on qualified improvement property. Additionally, the Consolidated Appropriations Act of 2021 was signed on December 27, 2020 which provided additional COVID relief provisions for businesses. The Company has evaluated the impact of both Acts and has determined that any impact is not material to its financial statements.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 21
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32857-109319

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SAB Topic 11.C)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330215-122817

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 17
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32809-109319

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 6.I.5.Q1)
-URI http://asc.fasb.org/extlink&oid=122134291&loc=d3e330036-122817

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 14
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32705-109319

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 270
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6424409&loc=d3e44925-109338

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-URI http://asc.fasb.org/topic&trid=2144680

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6424122&loc=d3e41874-109331

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08(h)(2))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690

+ Details

Stockholders' Equity - Summary of Stock Based Compensation Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 3,276	$ 1,500
Research and Development [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	734	348
General and Administrative [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation expense	$ 2,542	$ 1,152

Fair Value of Financial Instruments - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Mar. 07, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Percentage of probability of achieving milestone	72.00%	67.00%
Commercial milestones in applicable revenue, 2024	$ 100.0
Commercial milestones in applicable revenue, 2025	200.0
Essentialis, Inc. [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Maximum potential cash earnout payments	$ 21.2		$ 30.0

Leases (Tables)

12 Months Ended

Dec. 31, 2021

Leases [Abstract]

Schedule of Components of Lease Expense

The components of lease expense were as follows (in thousands):

	Year Ended
	December 31, 2021		December 31, 2020
Operating lease cost:
Operating lease cost	$	316	$	305
Variable lease cost		6		14
Short-term lease cost		24		15
Total operating lease cost	$	346	$	334

Finance lease cost:
Amortization of right-of-use assets	$	4	$	9
Interest on lease liabilities		—		2
Total finance lease cost	$	4	$	11

Schedule Of Supplemental Cash Flow Information Related To Leases

Supplemental cash flow information related to leases was as follows (in thousands):

	Year Ended
	December 31, 2021		December 31, 2020
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	277	$	336
Operating cash flows from finance leases	$	—	$	2
Financing cash flows from finance leases	$	8	$	17

Operating Lease Liability Maturity

The following is a schedule by year of future maturities of the Company’s operating lease liabilities as of December 31, 2021 (in thousands):

2022	$	315
2023		179
Total lease payments		494
Less interest		(37	)
Total	$	457

Stockholders' Equity - Additional Information (Detail) - USD ($)		12 Months Ended
	Jun. 26, 2020	Dec. 31, 2021	Dec. 31, 2020	Sep. 28, 2020	Oct. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Convertible preferred stock, shares authorized		10,000,000
Stock-based compensation expense		$ 3,276,000	$ 1,500,000
Expected dividend yield		0.00%	0.00%
Weighted average grant date fair value per option granted (in dollars per share)		$ 1.70	$ 1.76
Number of shares available for issuance under the plan on the first day of each year		79,864,310	79,615,692
Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Ownership interest of voting rights of all classes of stock (percent)		10.00%
2020 Inducement Equity Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for grant		1,425,000
Number of shares reserved for issuance				1,500,000
Stock Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Income tax benefits recognized from stock-based compensation		$ 0	$ 0
Number of options granted		3,462,810	824,150
Expected dividend yield		0.00%
Future stock-based compensation for unvested employee options granted and outstanding		$ 4,500,000
Future stock-based compensation, requisite service period		2 years 7 months 6 days
Stock options exercised, intrinsic value			$ 10,000
Stock Options [Member] \| 2014 Equity Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		4 years
Number of shares available for grant		1,226,105
Stock Options [Member] \| 2014 Equity Incentive Plan [Member] \| Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Percentage of fair market value		110.00%
Stock Options [Member] \| 2014 Equity Incentive Plan [Member] \| Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Contractual term of option		10 years
ISOs [Member] \| 2014 Equity Incentive Plan [Member] \| Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Contractual term of option		5 years
Performance-Based Options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options granted		708,750
Restricted Stock Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		4 years
Future stock-based compensation for unvested employee options granted and outstanding		$ 1,200,000
Stock units granted		177,941	751,633
Vesting percentage		100.00%
Weighted average grant-date fair value of all restricted stock units granted		$ 700,000	$ 300,000
Options exercisable at end of period		2 years 1 month 6 days
Restricted Stock Units [Member] \| 2014 Equity Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants expiration date		$ 3.85	$ 3.85
Stock units granted		177,941	751,633
Weighted average grant-date fair value of all restricted stock units granted		$ 1.05	$ 3.68
Series D Warrants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants outstanding (in shares)					256,064
Number of common stock purchased upon issuance of warrants					586,182
Exercise price of warrants (in dollars per share)					$ 12.30
Warrants exercised					0
Warrants to Purchase Stock [Member] \| 2010 and 2012 Convertible Promissory Notes [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants outstanding (in shares)		102,070
Exercise price of warrants (in dollars per share)		$ 24.35
Warrants term		10 years
Warrants expiration period		2024-11
Underwriter [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Warrants outstanding (in shares)		16,500
Exercise price of warrants (in dollars per share)		$ 35.70
Warrants term		10 years
Warrants expiration period		2024-11
Underwritten Public Offering [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of newly issued shares	34,848,484
Shares issued upon exercise of underwriters options	4,545,454
Price per unit	$ 1.65
Net proceeds from issuance of public offering	$ 53,700,000
Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares available for grant		27,967
Percentage of outstanding stock maximum		1.00%
Number of shares available for issuance under the plan on the first day of each year		55,936

Stockholders' Equity - Summary of Stock Option and Restricted Stock Unit Transactions (Detail) - Stock Options [Member] - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options granted	3,462,810	824,150
2014 Plan and Inducement Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Beginning balance	2,837,739	2,123,117
Options granted	3,462,810	824,150
Options exercised		(8,518)
Options canceled/forfeited	(175,000)	(101,010)
Ending balance	6,125,549	2,837,739	2,123,117
Options exercisable at end of period (shares)	2,814,405
Options vested and expected to vest at end of period (shares)	5,781,174
Weighted-Average Exercise Price per Share
Beginning balance (in dollars per share)	$ 4.18	$ 4.62
Options granted (in dollars per share)	2.13	2.79
Options exercised (in dollars per share)		1.96
Options canceled/forfeited (in dollars per share)	1.91	2.34
Ending balance (in dollars per share)	3.09	$ 4.18	$ 4.62
Options exercisable at end of period (in dollars per share)	4.15
Options vested and expected to vest at end of period (in dollars per share)	$ 3.14
Weighted Average Remaining Contractual Term
Options outstanding at end of period	7 years 11 months 8 days	7 years 7 months 13 days	7 years 10 months 13 days
Options exercisable at end of period	6 years 9 months 21 days
Options vested and expected to vest at end of period	7 years 10 months 17 days

Income Taxes - Significant Components of Company's Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Non-current deferred tax assets:
Federal and state net operating loss carryforwards	$ 48,542	$ 41,999
Research and other credits	3,312	2,803
Reserves and accruals	573	236
Fixed assets	59	63
Capital loss carryover	1,115	1,115
Stock based compensation	1,133	337
Lease liability	133	41
Other deferred tax assets	102	129
Gross non-current deferred tax assets	54,969	46,723
Intangible assets	(3,536)	(4,080)
Right-of-use assets	(118)	(39)
Total non-current deferred tax liabilities	(3,654)	(4,119)
Total deferred tax assets	51,315	42,604
Valuation allowance	$ (51,315)	$ (42,604)

Summary of Significant Accounting Policies - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) Bank Segment	Dec. 31, 2020
Schedule Of Significant Accounting Policies [Line Items]
Number of commercial banks \| Bank	1
Number of operating segments \| Segment	1
Estimated useful life	11 years
Expected dividend yield	0.00%	0.00%
ASU 2019-12 [Member]
Schedule Of Significant Accounting Policies [Line Items]
Change in accounting principle, accounting standards update, adopted	true
Change in accounting principle, accounting standards update, adoption date	Jan. 01, 2021
Change in accounting principle, accounting standards update, immaterial effect	true
Stock Options [Member]
Schedule Of Significant Accounting Policies [Line Items]
Expected dividend yield	0.00%
Essentialis, Inc. [Member]
Schedule Of Significant Accounting Policies [Line Items]
Net intangible assets acquired \| $	$ 22.0
Minimum [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives of property and equipment	3 years
Maximum [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives of property and equipment	5 years

Leases - Additional Information (Detail)	1 Months Ended		12 Months Ended
Leases - Additional Information (Detail)	Apr. 30, 2021 ft²	Jul. 31, 2019 USD ($) ft²	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Lessee Lease Description [Line Items]
Current finance lease liabilities			$ 0	$ 8,000
Finance Lease Liability Current Statement Of Financial Position Extensible List			Other current liabilities	Other current liabilities
Long-term lease liabilities			$ 175,000	$ 0
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]			Long-term lease liabilities	Long-term lease liabilities
Long-term finance lease liabilities			$ 0	$ 0
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]			Long-term lease liabilities	Long-term lease liabilities
Finance lease, weighted-average remaining lease term			1 year 4 months 24 days	4 months 24 days
Finance lease, discount rate				10.00%
Operating lease, weighted-average remaining lease term			1 year 4 months 24 days	4 months 24 days
Operating lease, discount rate			9.00%	10.00%
Redwood City, California [Member]
Lessee Lease Description [Line Items]
Area of operating lease \| ft²	6,368	6,368
Operating lease, description			In July 2019, the Company executed a non-cancellable lease agreement for 6,368 square feet of new space in Redwood City, California, which began in September 2019 and expired in May 2021. In April 2021, the Company executed a non-cancellable operating lease agreement for the same 6,368 square feet of space, which began in June 2021 and expires in May 2023.
Operating lease beginning date	2021-06	2019-09
Operating lease, expiration	2023-05	2021-05
Payment to acquire office furniture under operating lease		$ 1

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Accumulated Deficit [Member]
Balances at beginning at Dec. 31, 2019	$ 14,947	$ 45	$ 172,708	$ (157,806)
Balances at beginning (shares) at Dec. 31, 2019		44,658,054
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	1,500		1,500
Issuance of restricted stock units and option exercises under equity incentive plan	17		17
Issuance of restricted stock units and option exercises under equity incentive plan (shares)		109,154
Issuance of common stock	53,722	$ 35	53,687
Issuance of common stock (shares)		34,848,484
Net loss	(24,639)			(24,639)
Balances at ending at Dec. 31, 2020	45,547	$ 80	227,912	(182,445)
Balances at end (shares) at Dec. 31, 2020		79,615,692
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation	3,276		3,276
Issuance of restricted stock units under equity incentive plan (shares)		307,690
Tax withholding payments for net share-settled equity awards	(120)		(120)
Tax withholding payments for net share-settled equity awards (shares)		(59,072)
Net loss	(30,910)			(30,910)
Balances at ending at Dec. 31, 2021	$ 17,793	$ 80	$ 231,068	$ (213,355)
Balances at end (shares) at Dec. 31, 2021		79,864,310

Stockholders' Equity

12 Months Ended

Dec. 31, 2021

Equity [Abstract]

Stockholders' Equity

Note 9. Stockholders’ Equity

Convertible Preferred Stock

The Company is authorized to issue 10,000,000 shares of Preferred Stock.

Common Stock

On June 26, 2020, the Company sold 34,848,484 shares of its common stock, including 4,545,454 shares sold upon full exercise of the underwriters’ option to purchase additional shares, at a public offering price of $1.65 per share. The net proceeds of the offering were $53.7 million, after deducting the underwriting discount and other offering expenses.

Series D Warrants

The Company issued 256,064 Series D Warrants in October 2015, which were exercisable into 586,182 shares of the Company’s common stock, with an exercise price of $12.30. The warrants expired on October 15, 2020 and no warrants were exercised.

Accounting Treatment

The Company has accounted for the Series D Warrants in accordance with the guidance in ASC 815 Derivatives and Hedging. The Company was not required under any circumstance to settle any Series D Warrant exercise for cash. The Company therefore classified the value of the Series D Warrants as permanent equity.

Other Common Stock Warrants

As of December 31, 2021, the Company had 102,070 common stock warrants outstanding from the 2010/2012 convertible notes, with an exercise price of $24.35 and a term of 10 years expiring in November 2024. The Company also had outstanding 16,500 common stock warrants issued to the underwriter in the Company’s IPO, with an exercise price of $35.70 and a term of 10 years, expiring in November 2024.

Equity Incentive Plans

2014 Plan

The Company has the 2014 Equity Incentive Plan (the 2014 Plan). Under the 2014 Plan the Company may grant stock options, stock appreciation rights, restricted stock, restricted stock units, performance units or performance shares to employees, directors, advisors, and consultants. Options granted under the 2014 Plan may be incentive stock options (ISOs) or nonqualified stock options (NSOs). ISOs may be granted only to Company employees, including officers and directors.

The Board has the authority to determine to whom stock options will be granted, the number of options, the term, and the exercise price. Options are to be granted at an exercise price not less than fair value. For individuals holding more than 10% of the voting rights of all classes of stock, the exercise price of an option will not be less than 110% of fair value. The vesting period for service-based stock options is normally monthly over a period of 4 years from the vesting date. Performance-based grants have vesting contingent upon the achievement of certain performance criteria related to the Company’s commercialization of its therapeutics. The contractual term of an option is no longer than five years for ISOs for which the grantee owns greater than 10% of the voting power of all classes of stock and no longer than ten years for all other options. The terms and conditions governing restricted stock units is at the sole discretion of the Board.

As of December 31, 2021, a total of 1,226,105 shares are available for future grant under the 2014 Plan.

Inducement Plan

On September 28, 2020, the Company adopted the 2020 Inducement Equity Incentive Plan (the Inducement Plan), and subject to the adjustment provisions of the Inducement Plan, reserved 1,500,000 shares of the Company’s common stock for issuance pursuant to equity awards granted under the Inducement Plan. The Inducement Plan provides for the grant of equity-based awards, including non-statutory stock options, restricted stock units, restricted stock, stock appreciation rights, performance shares and performance units, and its terms are substantially similar to the Company’s 2014 Equity Incentive Plan.

In accordance with Rule 5635(c)(4) and Rule 5635(c)(3) of the Nasdaq Listing Rules, awards under the Inducement Plan may only be made to individuals not previously employees or non-employee directors of the Company (or following such individuals’ bona fide period of non-employment with the Company), as an inducement material to the individuals’ entry into employment with the Company, or, to the extent permitted by Rule 5635(c)(3) of the Nasdaq Listing Rules, in connection with a merger or acquisition.

As of December 31, 2021, a total of 1,425,000 shares are available for future grant under the Inducement Plan.

Stock-based compensation expense

The Company recognized stock-based compensation expense related to options and restricted stock units granted to employees, directors and consultants for the years ended December 31, 2021 and 2020 of $3.3 million and $1.5 million, respectively. The compensation expense is allocated on a departmental basis, based on the classification of the option holder. No income tax benefits have been recognized in the statements of operations for stock-based compensation arrangements during the year ended December 31, 2021 and December 31, 2020.

Stock compensation expense was allocated between departments as follows (in thousands).

	Year ended
	December 31, 2021		December 31, 2020
Research and development	$	734	$	348
General and administrative		2,542		1,152
Total	$	3,276	$	1,500

Stock Options

The Company granted options to purchase 3,462,810 and 824,150 of the Company’s common stock during the years ended December 31, 2021 and 2020, respectively. Of the total options granted during the year ended December 31, 2021, 708,750 were performance-based options. The fair value of each award granted was estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions.

	Year Ended
	December 31, 2021	December 31, 2020
Expected life (years)	5.5-6.0	5.5-6.1
Risk-free interest rate	0.6%-1.4%	0.4%-0.5%
Volatility	89%-108%	64%-96%
Weighted average volatility	104%	78%
Dividend rate	— %	— %

The Black-Scholes option-pricing model requires the use of highly subjective assumptions to estimate the fair value of stock-based awards. These assumptions include the following estimates:

•

Expected life: The expected life of stock options represents the period of time that the options are expected to be outstanding. Due to the lack of historical exercise history, the expected life of the Company’s service-based stock options has been determined utilizing the “simplified method”, based on the average of the contractual term of the options and the weighted-average vesting period. The expected life for the performance-based options was determined based on consideration of the contractual term of the stock options, an estimate of the date the performance criteria would be met and expectations of employee behavior.

•

Risk-free interest rate: The risk-free interest rate is based on the yields of U.S. Treasury securities with maturities similar to the expected time to liquidity.

•

Volatility: The estimated volatility rate used to value stock options granted during 2021 is based on the volatilities of the Company’s common stock for a historical period equal to the expected life of the stock options. For stock options granted during 2020, and prior to having sufficient history of the Company’s common stock volatility, the estimated volatility rate was based on the volatility of the Company’s common stock together with comparable companies in its industry.

•

Dividend rate: The Company has never declared or paid any cash dividends and does not presently plan to pay cash dividends in the foreseeable future. Consequently, the Company used an expected dividend yield of zero.

The following table summarizes stock option and restricted stock unit transactions for the years ended December 31, 2021 and 2020 as issued under the 2014 Plan and the Inducement Plan.

	Number of Options			Weighted- Average Exercise Price per		Weighted Average Remaining Contractual Term		Aggregate Intrinsic Value
	Outstanding			Share		(in years)		(in thousands)
Balance at December 1, 2020		2,123,117		$	4.62		7.87
Options granted		824,150		$	2.79
Options exercised		(8,518	)	$	1.96
Options canceled/forfeited		(101,010	)	$	2.34
Balance at December 31, 2020		2,837,739		$	4.18		7.62
Options granted		3,462,810		$	2.13
Options canceled/forfeited		(175,000	)	$	1.91
Balance at December 31, 2021		6,125,549		$	3.09		7.94	$	—
Options exercisable at December 31, 2021		2,814,405		$	4.15		6.81	$	—
Options vested and expected to vest at December 31, 2021		5,781,174		$	3.14		7.88	$	—

The weighted-average grant date fair value of employee options granted was $1.70 and $1.76 per share for the years ended December 31, 2021 and December 31, 2020, respectively. At December 31, 2021 total unrecognized employee stock-based compensation for options that are expected to vest was $4.5 million, which is expected to be recognized over the weighted-average remaining vesting period of 2.6 years. The intrinsic value of options exercised during the year ended December 31, 2020 was approximately $10,000.

Restricted Stock Units

There were 177,941 and 751,633 restricted stock units granted by the Company during the years ended December 31, 2021 and December 31, 2020, respectively, to employees and directors. The shares granted to directors were 100% vested on the grant date and represent compensation for past board services. The shares granted to employees typically vest annually over a period of four years. The shares were valued based on the Company’s common stock price on the grant date.

The following table summarizes restricted stock unit transactions for the years ended December 31, 2021 and 2020 as issued under the 2014 Plan:

	Number of Restricted Stock Units			Weighted- Average Grant-Date Fair Value per Share
Outstanding at January 1, 2020		—
Restricted stock units granted		751,633		$	3.68
Restricted stock units vested		(103,133	)	$	2.60
Restricted stock units cancelled		(67,500	)	$	3.85
Outstanding at December 31, 2020		581,000		$	3.85
Restricted stock units granted		177,941		$	1.05
Restricted stock units vested		(323,191	)	$	2.31
Outstanding at December 31, 2021		435,750		$	3.85

The fair value of all restricted stock units vested during the year ended December 31, 2021 and 2020 was $0.7 million and $0.3 million, respectively. At December 31, 2021 total unrecognized employee stock-based compensation related to restricted stock units was $1.2 million, which is expected to be recognized over the weighted-average remaining vesting period of 2.1 years.

2014 Employee Stock Purchase Plan

The Company’s board of directors and stockholders have adopted the 2014 Employee Stock Purchase Plan (the ESPP). The ESPP has become effective, and the board of directors will implement commencement of offers thereunder in its discretion. A total of 27,967 shares of the Company’s common stock has been made available for sale under the ESPP. In addition, the ESPP provides for annual increases in the number of shares available for issuance under the plan on the first day of each year beginning in the year following the initial date that the board of directors authorizes commencement, equal to the least of:

•

1.0% of the outstanding shares of the Company’s common stock on the first day of such year;

•

55,936 shares; or

•

such amount as determined by the board of directors.

As of December 31, 2021, there were no purchases by employees under this plan.

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Schedule of Geographical Distribution of Loss before Income Taxes

The geographical distribution of loss before income taxes are summarized below (in thousands).

	December 31,
	2021			2020
United States	$	(30,453	)	$	(22,197	)
Foreign		(457	)		(2,442	)
Loss before income taxes	$	(30,910	)	$	(24,639	)

Provision for Income Tax Benefit by Applying Statutory Federal Income Tax Rate to Operating Loss

The provision for income tax benefit differs from the amount estimated by applying the statutory federal income tax rate to the operating loss due to the following (in thousands).

	December 31,
	2021			2020
Tax (benefit) on the loss before income tax expense computed at the federal statutory rate	$	(6,501	)	$	(5,174	)
State tax (benefit) at statutory rate, net of federal benefit		(2,342	)		(2,293	)
Foreign rate differential		12			51
Change in valuation allowance		8,711			8,231
Change in research and development credits		(364	)		(303	)
Stock based compensation—ISOs		52			71
Change in fair value of warrants		(107	)		(2,444	)
Change in fair value of contingent consideration		(153	)		911
Change in net operating loss true up		712			846
Other		(20	)		104
Provision for income tax benefit	$	—		$	—

Significant Components of Company's Deferred Tax Assets and Liabilities

Significant components of the Company’s deferred tax assets and liabilities are as follows at December 31, 2021 and 2020 (in thousands).

	December 31,
	2021			2020
Non-current deferred tax assets:
Federal and state net operating loss carryforwards	$	48,542		$	41,999
Research and other credits		3,312			2,803
Reserves and accruals		573			236
Fixed assets		59			63
Capital loss carryover		1,115			1,115
Stock based compensation		1,133			337
Lease liability		133			41
Other deferred tax assets		102			129
Gross non-current deferred tax assets		54,969			46,723
Intangible assets		(3,536	)		(4,080	)
Right-of-use assets		(118	)		(39	)
Total non-current deferred tax liabilities		(3,654	)		(4,119	)
Total deferred tax assets		51,315			42,604
Valuation allowance		(51,315	)		(42,604	)
Net deferred tax assets	$	—		$	—

Summary of Gross Unrecognized Tax Benefits

The following tables summarize the activities of gross unrecognized tax benefits (in thousands).

	December 31,
	2021		2020
Beginning balance	$	1,323	$	1,111
Decrease related to prior year tax positions		—		(4	)
Increase related to current year tax positions		234		216
Ending balance	$	1,557	$	1,323

Leases - Schedule of Future Maturities (Detail) $ in Thousands	Dec. 31, 2021 USD ($)
Leases [Abstract]
2022	$ 315
2023	179
Total lease payments	494
Less interest	(37)
Total	$ 457

Subsequent Events

12 Months Ended

Dec. 31, 2021

Subsequent Events [Abstract]

Subsequent Events

Note 14. Subsequent Events

The Company has evaluated its subsequent events from December 31, 2021 through the date these consolidated financial statements were issued and has determined that there are no subsequent events requiring disclosure in these consolidated financial statements other than the item noted below.

Underwritten Public Offering

On March 31, 2022, the Company sold 40,000,000 shares of its common stock at a public offering price of $0.25, and for certain investors, in lieu of common stock, pre-funded warrants to purchase 20,000,000 shares of its common stock at a public offering price of $0.24 per pre-funded warrant, which represents the per share public offering price for the common stock less the $0.01 per share exercise price for each pre-funded warrant. The pre-funded warrants are immediately exercisable and may be exercised at any time until all of the pre-funded warrants are exercised in full. Each share of common stock or pre-funded warrant was sold together with one, immediately exercisable common warrant with a five year term to purchase one share of common stock at an exercise price of $0.30 per share. The net proceeds of the offering were $13.9 million, after deducting the underwriting discount and other estimated offering expenses.

Other Financial Statement Details - Future Amortization Expense (Detail) - Patents And Trademark [Member] $ in Thousands	Dec. 31, 2021 USD ($)
Finite Lived Intangible Assets [Line Items]
2022	$ 1,944
2023	1,944
2024	1,944
2025	1,944
2026 and thereafter	4,861
Net Amount	$ 12,637

Other Financial Statement Details

12 Months Ended

Dec. 31, 2021

Other Financial Statement Details Disclosure [Abstract]

Other Financial Statement Details

Note 5. Other Financial Statement Details

Property and Equipment, Net

Property and equipment are summarized in the following table (in thousands).

	December 31, 2021			December 31, 2020
Computer hardware	$	72		$	53
Furniture and fixtures		29			1
		101			54
Less accumulated depreciation and amortization		(68	)		(35	)
Total	$	33		$	19

Depreciation expense was approximately $19,000 and $11,000 for the years ended December 31, 2021 and December 31, 2020, respectively.

Intangible Assets, Net

Intangible assets consist of the following (in thousands).

December 31, 2021

December 31, 2020

Amount

Accumulated

Amortization

Net

Amount

Accumulated

Amortization

Net

Amount

Patents and merger costs

22,003

(9,366

)

12,637

22,003

(7,422

)

14,581

Future amortization expense for intangible assets over their remaining useful lives is as follows (in thousands).

Year ending December 31	Patents and trademarks
2022		1,944
2023		1,944
2024		1,944
2025		1,944
2026 and thereafter		4,861
Total	$	12,637

Amortization expense was $1.9 million for the year ended December 31, 2021 and 2020.

Defined Contribution Plan - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Compensation And Retirement Disclosure [Abstract]
Matching contribution by Company	$ 0	$ 0

Warrant Liabilities - Fair Value of Convertible Preferred Stock Warrant Liability (Detail)	Dec. 31, 2021	Dec. 31, 2020
Volatility [Member] \| 2018 PIPE Warrant Liability [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.95	0.88
Contractual Term [Member] \| 2018 PIPE Warrant Liability [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement term	2 years	3 years
Expected Dividend Yield [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0
Risk-free Rate [Member] \| 2018 PIPE Warrant Liability [Member]
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Measurement input	0.0072	0.0017

Other Financial Statement Details (Tables)

12 Months Ended

Dec. 31, 2021

Other Financial Statement Details Disclosure [Abstract]

Schedule of Property and Equipment

Property and equipment are summarized in the following table (in thousands).

	December 31, 2021			December 31, 2020
Computer hardware	$	72		$	53
Furniture and fixtures		29			1
		101			54
Less accumulated depreciation and amortization		(68	)		(35	)
Total	$	33		$	19

Schedule of Intangible Assets

Intangible assets consist of the following (in thousands).

December 31, 2021

December 31, 2020

Amount

Accumulated

Amortization

Net

Amount

Accumulated

Amortization

Net

Amount

Patents and merger costs

22,003

(9,366

)

12,637

22,003

(7,422

)

14,581

Schedule of Future Amortization Expense

Future amortization expense for intangible assets over their remaining useful lives is as follows (in thousands).

Year ending December 31	Patents and trademarks
2022		1,944
2023		1,944
2024		1,944
2025		1,944
2026 and thereafter		4,861
Total	$	12,637

Defined Contribution Plan

12 Months Ended

Dec. 31, 2021

Compensation And Retirement Disclosure [Abstract]

Defined Contribution Plan

Note 13. Defined Contribution Plan

The Company sponsors a 401(k) Plan, which stipulates that eligible employees can elect to contribute to the 401(k) Plan, subject to certain limitations of eligible compensation. The Company may match employee contributions in amounts to be determined at the Company’s sole discretion. The Company made no matching contributions during the year ended December 31, 2021 and 2020.

- Definition

The entire disclosure for retirement benefits.

+ References

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+ Details

Leases

12 Months Ended

Dec. 31, 2021

Leases [Abstract]

Leases

Note 7. Leases

Leases

In July 2019, the Company executed a non-cancellable lease agreement for 6,368 square feet of new space in Redwood City, California, which began in September 2019 and expired in May 2021. In April 2021, the Company executed a non-cancellable operating lease agreement for the same 6,368 square feet of space, which began in June 2021 and expires in May 2023. The lease that expired in May 2021 also provided the Company with the right to use office furniture in the space and allowed the purchase of this furniture at the end of the lease term for $1. The Company has accounted for both leases of office space as operating leases. The office furniture included in the lease that expired in May 2021 was accounted for as a finance lease based on its relative standalone price as compared to the office space.

The Company’s operating lease ROU assets, finance ROU assets, current operating lease liabilities and long-term operating lease liabilities each appear as a separate line within the Company’s consolidated balance sheet. The Company’s current finance lease liabilities were $0 and approximately $8,000 as of December 31, 2021 and December 31, 2020, respectively, and are included in other current liabilities on the consolidated balance sheet. As of December 31, 2021 and December 31, 2020, the Company’s long-term operating lease liabilities were $0.2 million and $0, respectively. There were no long-term finance lease liabilities recorded as of December 31, 2021 or December 31, 2020.

The components of lease expense were as follows (in thousands):

	Year Ended
	December 31, 2021		December 31, 2020
Operating lease cost:
Operating lease cost	$	316	$	305
Variable lease cost		6		14
Short-term lease cost		24		15
Total operating lease cost	$	346	$	334

Finance lease cost:
Amortization of right-of-use assets	$	4	$	9
Interest on lease liabilities		—		2
Total finance lease cost	$	4	$	11

Supplemental cash flow information related to leases was as follows (in thousands):

	Year Ended
	December 31, 2021		December 31, 2020
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	$	277	$	336
Operating cash flows from finance leases	$	—	$	2
Financing cash flows from finance leases	$	8	$	17

The following is a schedule by year of future maturities of the Company’s operating lease liabilities as of December 31, 2021 (in thousands):

2022	$	315
2023		179
Total lease payments		494
Less interest		(37	)
Total	$	457

The weighted-average remaining lease term was 1.4 and 0.4 years as of December 31, 2021 and December 31, 2020, respectively, for both the operating leases and finance leases. The weighted average discount rate related to the Company’s operating lease liabilities was 9% as of December 31, 2021, and was 10% as of December 31, 2020 for both the operating leases and finance leases. The Company lease discount rates are based on estimates of its incremental borrowing rate, as the discount rates implicit in the Company’s leases cannot be readily determined. As the Company does not have any outstanding debt the Company estimates the incremental borrowing rate based on its estimated credit rating and available market information.

Warrant Liabilities

12 Months Ended

Dec. 31, 2021

Text Block [Abstract]

Warrant Liabilities

Note 6. Warrant Liabilities

The Company has issued multiple warrant series, of which the Series C Warrants, the 2017 PIPE Warrants and the 2018 PIPE Warrants (the Warrants) were determined to be liabilities pursuant to the guidance established by ASC 815 Derivatives and Hedging.

Accounting Treatment

The Company accounts for the Warrants in accordance with the guidance in ASC 815. As indicated above, the Company may be obligated to settle the Warrants in cash in the case of a Fundamental Transaction.

The Company classified the Warrants as long-term liabilities at their fair value and will re-measure the warrants at each balance sheet date until they are exercised or expire. Any change in the fair value is recognized as other income (expense) in the Company’s consolidated statements of operations.

Series C Warrants

The Series C Warrants were exercisable into 118,083 shares of the Company’s common stock prior to their expiration on March 5, 2020, and no warrants were exercised prior to expiration

Warrants Issued as Part of the Units in the 2017 PIPE Offering

The 2017 PIPE Warrants were issued on December 15, 2017 in the 2017 PIPE Offering, pursuant to a Warrant Agreement with each of the investors in the 2017 PIPE Offering, and entitled the holders to purchase 6,024,425 shares of the Company’s common stock at an exercise price equal to $2.00 per share, subject to certain adjustments. The $10.8 million decrease in the fair value of the liability for the 2017 PIPE Warrants during the year ended December 31, 2020 was recorded as other income in the consolidated statements of operations. The warrants expired on December 15, 2020, and no warrants were exercised prior to expiration.

Warrants Issued as Part of the Units in the 2018 PIPE Offering

The 2018 PIPE Warrants were issued on December 19, 2018 in the 2018 PIPE Offering, pursuant to a Warrant Agreement with each of the investors in the 2018 PIPE Offering, and entitle the holders to purchase 513,617 shares of the Company’s common stock at an exercise price equal to $2.00 per share, subject to adjustment as discussed below, at any time commencing upon issuance of the 2018 PIPE Warrants and terminating on December 21, 2023.

The exercise price and number of shares of common stock issuable upon exercise of the 2018 PIPE Warrants may be adjusted in certain circumstances, including in the event of a stock split, stock dividend, extraordinary dividend, or recapitalization, reorganization, merger or consolidation. However, the exercise price of the 2018 PIPE Warrants will not be reduced below $2.00.

In the event of a change of control of the Company, the holders of unexercised warrants may present their unexercised warrants to the Company, or its successor, to be purchased by the Company, or its successor, in an amount equal to the per share value determined by the Black Scholes methodology.

As of December 31, 2021 and 2020, the fair value of the 2018 PIPE Warrants was estimated at approximately $31,000 and $0.5 million, respectively. The $0.5 million and $0.8 million decrease in the fair value of the liability for the 2018 PIPE Warrants during the years ended December 31, 2021 and 2020, respectively, was recorded as Other income in the consolidated statements of operations.

The Company has calculated the fair value of the 2018 PIPE Warrants using a Black-Scholes pricing model. The following summarizes certain key assumptions used in estimating the fair values.

	December 31, 2021			December 31, 2020
Volatility		95	%		88	%
Contractual term (years)		2.0			3.0
Expected dividend yield		—	%		—	%
Risk-free rate		0.72	%		0.17	%

The Black-Scholes pricing model requires the use of highly subjective assumptions to estimate the fair value of stock-based awards. These assumptions include the following estimates.

•

Volatility: The Company calculated the estimated volatility rate as of December 31, 2021, based on the volatility of its common stock over a period equal to the expected life of the warrants. The volatility rate

estimated as of December 31, 2020, prior to having sufficient history of the Company’s common stock volatility, was based on the volatility of the Company’s common stock together with comparable companies in its industry.

•

Contractual term: The expected life of the warrants, which is based on the contractual term of the warrants.

•

Expected dividend yield: The Company has never declared or paid any cash dividends and does not currently plan to pay cash dividends in the foreseeable future. Consequently, the Company used an expected dividend yield of zero.

•

Risk-free rate: The risk-free interest rate is based on the U.S. Treasury rate for similar periods as the expected life of the warrants.

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net loss	$ (30,910)	$ (24,639)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	1,963	1,954
Noncash lease expense	288	283
Stock-based compensation expense	3,276	1,500
Change in fair value of stock warrants	(508)	(11,637)
Change in fair value of contingent consideration	(731)	4,340
Change in operating assets and liabilities:
Prepaid expenses, other current assets and other assets	(139)	(549)
Accounts payable	(235)	1,494
Accrued compensation	(277)	722
Accrued clinical trial site costs	(369)	1,790
Operating lease liabilities	(263)	(305)
Other liabilities	135	(177)
Net cash used in operating activities	(27,770)	(25,224)
Cash flows from investing activities:
Purchases of property and equipment	(22)	(7)
Net cash used in investing activities	(22)	(7)
Cash flows from financing activities:
Proceeds from sale of common stock and common stock warrants, net of costs		53,722
Tax withholding payments for net share-settled equity awards	(120)
Proceeds from stock option exercises		17
Principal paid on finance lease liabilities	(8)	(17)
Net cash (used in) provided by financing activities	(128)	53,722
Net (decrease) increase in cash and cash equivalents	(27,920)	28,491
Cash and cash equivalents, beginning of period	49,224	20,733
Cash and cash equivalents, end of period	21,304	49,224
Supplemental disclosure of non-cash investing and financing information
Right-of use assets obtained in exchange for operating lease obligations	$ 581
Purchases of property and equipment in accounts payable		$ 1

Fair Value of Financial Instruments (Tables)

12 Months Ended

Dec. 31, 2021

Fair Value Disclosures [Abstract]

Summary of Financial Instruments Measured at Fair Value on Recurring Basis

The following table sets forth the Company’s financial instruments that were measured at fair value on a recurring basis by level within the fair value hierarchy (in thousands).

	Fair Value Measurements at December 31, 2021
	Total		Level 1		Level 2		Level 3
Liabilities
2018 PIPE warrant liability	$	31	$	—	$	—	$	31
Essentialis purchase price contingency liability		9,547		—		—		9,547
Total common stock warrant and contingent consideration liability	$	9,578	$	—	$	—	$	9,578

	Fair Value Measurements at December 31, 2020
	Total		Level 1		Level 2		Level 3
Liabilities
2018 PIPE warrant liability	$	539	$	—	$	—	$	539
Essentialis purchase price contingency liability		10,278		—		—		10,278
Total common stock warrant and contingent consideration liability	$	10,817	$	—	$	—	$	10,817

Summary of Changes in Fair Value of Level 3 Financial Instruments

The following table sets forth a summary of the changes in the fair value of the Company’s Level 3 liabilities (dollars in thousands).

	Series C Warrants					2017 PIPE Warrants						2018 PIPE Warrants					Purchase Price
	Number of					Number of						Number of					Contingent
	Warrants			Liability		Warrants			Liability			Warrants		Liability			Liability
Balance at January 1, 2020		118,083		$	—		6,024,425		$	10,822			513,617	$	1,354		$	5,938
Expiration of Series C Warrants		(118,083	)		—		—			—			—		—			—
Expiration of 2017 PIPE Warrants		—			—		(6,024,425	)		(10,822	)		—		—			—
Change in value of 2018 PIPE Warrants		—			—		—			—			—		(815	)		—
Change in value of contingent liability		—			—		—			—			—		—			4,340
Balance at December 31, 2020		—			—		—			—			513,617		539			10,278
Change in value of 2018 PIPE Warrants		—			—		—			—			—		(508	)		—
Change in value of contingent liability due to estimated future revenue milestones		—			—		—			—			—		—			3,249
Change in value of contingent liability due to assignment of rights to Soleno		—			—		—			—			—		—			(3,980	)
Balance at December 31, 2021		—		$	—		—		$	—			513,617	$	31		$	9,547

- Definition

Tabular disclosure of financial instruments measured at fair value, including those classified in shareholders' equity measured on a recurring or nonrecurring basis. Disclosures include, but are not limited to, fair value measurements recorded and the reasons for the measurements, level within the fair value hierarchy in which the fair value measurements are categorized and transfers between levels 1 and 2. Nonrecurring fair value measurements are those that are required or permitted in the statement of financial position in particular circumstances.

+ References + Details

Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Income Tax Contingency [Line Items]
Increase (decrease) in valuation allowance	$ 8,700,000
Unrecognized assets and liabilities related to uncertain tax positions	1,600,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	0	$ 0
Unrecognized tax benefit offset by change in valuation allowance	1,600,000
Internal Revenue Service (IRS) [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards	500,000
U.S. Federal Jurisdiction [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards	189,300,000
Operating loss carryforwards, carried forward indefinitely	82,900,000
U.S. Federal Jurisdiction [Member] \| Research Tax Credit Carryforward [Member]
Income Tax Contingency [Line Items]
Tax credit carryforwards	2,100,000
State Tax Jurisdiction [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards	116,400,000
State Tax Jurisdiction [Member] \| Research Tax Credit Carryforward [Member]
Income Tax Contingency [Line Items]
Tax credit carryforwards	1,200,000
Foreign Tax Authority [Member] \| Her Majesty's Revenue and Customs (HMRC) [Member]
Income Tax Contingency [Line Items]
Operating loss carryforwards	$ 2,500,000

Net loss per share

12 Months Ended

Dec. 31, 2021

Earnings Per Share [Abstract]

Net loss per share

Note 12. Net loss per share

Basic net loss per share is computed by dividing net loss by the weighted-average number of common stock actually outstanding during the period. Diluted net loss per share is computed by dividing net loss by the weighted-average number of common stock outstanding and dilutive potential common stock that would be issued upon the exercise or vesting of common stock awards and exercise of common stock warrants. For the years ended December 31, 2021 and 2020, the effect of issuing the potential common stock is anti-dilutive due to the net losses in those periods and the number of shares used to compute basic and diluted earnings per share are the same in each of those periods.

The following potentially dilutive securities outstanding have been excluded from the computations of diluted weighted-average shares outstanding because such securities have an antidilutive impact due to losses reported (in common stock equivalent shares).

	As of December 31,
	2021		2020
Warrants issued to 2010/2012 convertible note holders to purchase common stock		102,070		102,070
Options to purchase common stock		6,125,549		2,837,739
Outstanding restricted stock units		435,750		581,000
Warrants issued to underwriter to purchase common stock		16,500		16,500
2018 PIPE warrants		513,617		513,617
Total		7,193,486		4,050,926

Subsequent Events - Additional Information (Details) - Underwritten Public Offering [Member] - USD ($) $ / shares in Units, $ in Millions	Mar. 31, 2022	Jun. 26, 2020
Subsequent Event [Line Items]
Issuance of common stock (shares)		34,848,484
Price per unit		$ 1.65
Subsequent Event [Member]
Subsequent Event [Line Items]
Issuance of common stock (shares)	40,000,000
Price per unit	$ 0.25
Number of common stock purchased upon issuance of warrants	20,000,000
Public offering price per pre-funded warrant	$ 0.24
Per share exercise price for pre-funded warrant	$ 0.01
Measurement term	5 years
Exercise price of warrants exercised	$ 0.30
Proceeds from offering after deducting underwriting discount and other estimated offering expenses	$ 13.9

Other Financial Statement Details - Schedule of Property and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 101	$ 54
Less accumulated depreciation and amortization	(68)	(35)
Total	33	19
Computer Hardware [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	72	53
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 29	$ 1

Net loss per share (Tables)

12 Months Ended

Dec. 31, 2021

Earnings Per Share [Abstract]

Schedule of Potentially Dilutive Securities Outstanding Excluded from Computations of Diluted Weighted-Average Shares Outstanding

	As of December 31,
	2021		2020
Warrants issued to 2010/2012 convertible note holders to purchase common stock		102,070		102,070
Options to purchase common stock		6,125,549		2,837,739
Outstanding restricted stock units		435,750		581,000
Warrants issued to underwriter to purchase common stock		16,500		16,500
2018 PIPE warrants		513,617		513,617
Total		7,193,486		4,050,926

Leases - Schedule of Components of Lease Expense (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Leases [Abstract]
Operating lease cost	$ 316	$ 305
Variable lease cost	6	14
Short-term lease cost	24	15
Total operating lease cost	346	334
Amortization of right-of-use assets	4	9
Interest on lease liabilities		2
Total finance lease cost	$ 4	$ 11

Fair Value of Financial Instruments - Summary of Financial Instruments Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Liabilities
Contingent liability for Essentialis purchase price	$ 9,547	$ 10,278
2018 PIPE Warrant Liability [Member]
Liabilities
Warrant liability	31	539
Fair Value, Measurements, Recurring [Member]
Liabilities
Total common stock warrant and contingent consideration liability	9,578	10,817
Fair Value, Measurements, Recurring [Member] \| Derivative Financial Instruments, Liabilities \| 2018 PIPE Warrant Liability [Member]
Liabilities
Warrant liability	31	539
Essentialis, Inc. [Member] \| Fair Value, Measurements, Recurring [Member]
Liabilities
Contingent liability for Essentialis purchase price	9,547	10,278
Level 3 [Member] \| Fair Value, Measurements, Recurring [Member]
Liabilities
Total common stock warrant and contingent consideration liability	9,578	10,817
Level 3 [Member] \| Fair Value, Measurements, Recurring [Member] \| Derivative Financial Instruments, Liabilities \| 2018 PIPE Warrant Liability [Member]
Liabilities
Warrant liability	31	539
Level 3 [Member] \| Essentialis, Inc. [Member] \| Fair Value, Measurements, Recurring [Member]
Liabilities
Contingent liability for Essentialis purchase price	$ 9,547	$ 10,278

Warrant Liabilities - Additional Information (Detail)	12 Months Ended
Warrant Liabilities - Additional Information (Detail)	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($)	Dec. 19, 2018 $ / shares shares	Dec. 15, 2017 $ / shares shares
Class Of Warrant Or Right [Line Items]
Change in fair value of stock warrants \| $	$ (508,000)	$ (11,637,000)
Expected Dividend Yield [Member]
Class Of Warrant Or Right [Line Items]
Measurement input	0
Series C Warrant [Member]
Class Of Warrant Or Right [Line Items]
Number of common stock purchased upon issuance of warrants	118,083
Warrants exercised prior to expiration	0
Tender offer expiration date	Mar. 05, 2020
2017 PIPE Warrant Liability [Member]
Class Of Warrant Or Right [Line Items]
Number of common stock purchased upon issuance of warrants				6,024,425
Warrants exercised prior to expiration	0
Tender offer expiration date	Dec. 15, 2020
Exercise price of warrants exercised \| $ / shares				$ 2.00
Warrant issuance description	The 2017 PIPE Warrants were issued on December 15, 2017 in the 2017 PIPE Offering, pursuant to a Warrant Agreement with each of the investors in the 2017 PIPE Offering, and entitled the holders to purchase 6,024,425 shares of the Company’s common stock at an exercise price equal to $2.00 per share, subject to certain adjustments.
Change in fair value of stock warrants \| $		(10,800,000)
2018 PIPE Warrant Liability [Member]
Class Of Warrant Or Right [Line Items]
Number of common stock purchased upon issuance of warrants			513,617
Exercise price of warrants exercised \| $ / shares			$ 2.00
Warrant issuance description	The 2018 PIPE Warrants were issued on December 19, 2018 in the 2018 PIPE Offering, pursuant to a Warrant Agreement with each of the investors in the 2018 PIPE Offering, and entitle the holders to purchase 513,617 shares of the Company’s common stock at an exercise price equal to $2.00 per share, subject to adjustment as discussed below, at any time commencing upon issuance of the 2018 PIPE Warrants and terminating on December 21, 2023.
Change in fair value of stock warrants \| $	$ (500,000)	(800,000)
Fair value of estimated warrants \| $	$ 31,000	$ 500,000
2018 PIPE Warrant Liability [Member] \| Minimum [Member]
Class Of Warrant Or Right [Line Items]
Exercise price of warrants exercised \| $ / shares	$ 2.00

Going Concern and Management's Plans

12 Months Ended

Dec. 31, 2021

Cash And Cash Equivalents [Abstract]

Going Concern and Management's Plans

Note 2. Going Concern and Management’s Plans

The Company had a net loss of $30.9 million during 2021 and has an accumulated deficit of $213.4 million at December 31, 2021 resulting from having incurred losses since its inception. The Company had $21.3 million of cash and cash equivalents on hand at December 31, 2021 and used $27.8 million of cash in its operating activities during 2021. The Company has financed its operations principally through issuances of equity securities. In March 2022, the Company completed a public offering of shares of its common stock and pre-funded warrants and raised $13.9 million in net proceeds. Each share of common stock or pre-funded warrant was sold together with one immediately exercisable common warrant to purchase one share of common stock.

The accompanying consolidated financial statements have been prepared under the assumption the Company will continue to operate as a going concern, which contemplates the realization of assets and the settlement of liabilities in the normal course of business. The consolidated financial statements do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets or the amounts of liabilities that may result from uncertainty related to the Company’s ability to continue as a going concern.

The Company expects to continue incurring losses for the foreseeable future and will be required to raise additional capital to complete its clinical trials, pursue product development initiatives, obtain regulatory approval and penetrate markets for the sale of its products. Management believes that the Company will continue to have access to capital resources through possible public or private equity offerings, debt financings, corporate collaborations or other means, but the Company’s access to such capital resources is uncertain and is not assured. If the Company is unable to secure additional capital, it may be required to curtail its clinical trials and development of new products and take additional measures to reduce expenses in order to conserve its cash in amounts sufficient to sustain operations and meet its obligations. These measures could cause significant delays in the Company’s efforts to complete its clinical trials and commercialize its products, which are critical to the realization of its business plan and the future operations of the Company.

Management believes that the Company does not have sufficient capital resources to sustain operations through at least the next twelve months from the date of this filing. Additionally, in view of the Company’s expectation to incur significant losses for the foreseeable future it will be required to raise additional capital resources in order to fund its operations, although the availability of, and the Company’s access to such resources is not assured. Accordingly, management believes that there is substantial doubt regarding the Company’s ability to continue operating as a going concern through at least the next twelve months from the date of this filing.