aTyr Pharma (ATYR) 10-Q 14 Nov 22 2022 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2022	Nov. 08, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q3
Document Quarterly Report	true
Document Transition Report	false
Security Exchange Name	NASDAQ
Trading Symbol	LIFE
Entity Registrant Name	ATYR PHARMA, INC.
Entity Central Index Key	0001339970
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		29,009,382
Entity File Number	001-37378
Entity Tax Identification Number	20-3435077
Entity Address, Address Line One	3545 John Hopkins Court
Entity Address, Address Line Two	Suite #250
Entity Address, City or Town	San Diego
Entity Address, State or Province	CA
Entity Incorporation, State or Country Code	DE
Entity Address, Postal Zip Code	92121
City Area Code	858
Local Phone Number	731-8389
Title of 12(b) Security	Common Stock, par value $0.001 per share

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 18,359	$ 2,336
Available-for-sale investments	59,015	105,575
Other receivables	873	435
Prepaid expenses	6,386	5,223
Total current assets	84,633	113,569
Restricted cash	2,239
Property and equipment, net	1,275	543
Operating lease, right-of-use assets	6,971	1,267
Financing lease, right-of-use assets	768
Other assets	169	158
Total assets	96,055	115,537
Current liabilities:
Accounts payable	3,129	1,031
Accrued expenses	7,269	4,002
Current portion of operating lease liability	657	980
Current portion of financing lease liability	158
Total current liabilities	11,213	6,013
Long-term operating lease liability, net of current portion	7,218	398
Long-term financing lease liability, net of current portion	618
Commitments and contingencies (Note 4)
Stockholders’ equity:
Preferred stock, $0.001 par value per share; 5,000,000 undesignated authorized shares as of September 30, 2022 (unaudited) and December 31, 2021; no shares issued or outstanding as of September 30, 2022 (unaudited) and December 31, 2021
Common stock, $0.001 par value per share; 85,000,000 and 42,500,000 authorized shares as of September 30, 2022 (unaudited) and December 31, 2021, respectively; issued and outstanding shares - 29,009,382 and 27,793,035 as of September 30, 2022 (unaudited) and December 31, 2021, respectively	29	28
Additional paid-in capital	487,937	481,832
Accumulated other comprehensive loss	(669)	(263)
Accumulated deficit	(410,113)	(372,296)
Total aTyr Pharma, Inc. stockholders’ equity	77,184	109,301
Noncontrolling interest in Pangu BioPharma Limited	(178)	(175)
Total stockholders’ equity	77,006	109,126
Total liabilities and stockholders’ equity	$ 96,055	$ 115,537

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2022	Dec. 31, 2021
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	85,000,000	42,500,000
Common stock, shares issued	29,009,382	27,793,035
Common stock, shares outstanding	29,009,382	27,793,035

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Operating expenses:
Research and development	$ 9,867	$ 5,138	$ 27,898	$ 17,309
General and administrative	3,625	2,590	10,556	8,066
Total operating expenses	13,492	7,728	38,454	25,375
Loss from operations	(13,492)	(7,728)	(38,454)	(25,375)
Total other income (expense), net	247	59	634	159
Consolidated net loss	(13,245)	(7,669)	(37,820)	(25,216)
Net loss attributable to noncontrolling interest in Pangu BioPharma Limited	1	2	3	7
Net loss attributable to aTyr Pharma, Inc.	$ (13,244)	$ (7,667)	$ (37,817)	$ (25,209)
Net loss per share, basic	$ (0.46)	$ (0.42)	$ (1.34)	$ (1.56)
Net loss per share, diluted	$ (0.46)	$ (0.42)	$ (1.34)	$ (1.56)
Shares used in computing net loss per share, basic	28,663,047	18,159,231	28,184,698	16,145,351
Shares used in computing net loss per share, diluted	28,663,047	18,159,231	28,184,698	16,145,351

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Statement of Comprehensive Income [Abstract]
Consolidated net loss	$ (13,245)	$ (7,669)	$ (37,820)	$ (25,216)
Other comprehensive loss:
Change in unrealized gain (loss) on available-for-sale investments, net of tax	141	(8)	(406)	(26)
Comprehensive loss	(13,104)	(7,677)	(38,226)	(25,242)
Comprehensive loss attributable to noncontrolling interest in Pangu BioPharma Limited	1	2	3	7
Comprehensive loss attributable to aTyr Pharma, Inc. common stockholders	$ (13,103)	$ (7,675)	$ (38,223)	$ (25,235)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Other Comprehensive Gain/(Loss) [Member]	Accumulated Deficit [Member]	Noncontrolling Interest [Member]
Beginning balance at Dec. 31, 2020	$ 31,484	$ 11	$ 370,210	$ (43)	$ (338,528)	$ (166)
Begining balance, Shares at Dec. 31, 2020		11,018,954
Issuance of common stock upon release of restricted stock units, shares		4,177
Issuance of common stock from at-the-market offerings, net of offering costs	9,621	$ 2	9,619
Issuance of common stock from at the market offerings, net of offering costs, shares		1,988,254
Issuance of common stock from committed purchase agreement, net of offering costs	15,236	$ 3	15,233
Issuance of common stock from committed purchase agreement, net of offering costs, shares		3,000,000
Stock-based compensation	360		360
Net unrealized loss on investments, net of tax	(14)			(14)
Net loss	(7,155)				(7,151)	(4)
Ending balance at Mar. 31, 2021	49,532	$ 16	395,422	(57)	(345,679)	(170)
Ending balance, Shares at Mar. 31, 2021		16,011,385
Beginning balance at Dec. 31, 2020	31,484	$ 11	370,210	(43)	(338,528)	(166)
Begining balance, Shares at Dec. 31, 2020		11,018,954
Net unrealized loss on investments, net of tax	(26)
Net loss	(25,216)
Ending balance at Sep. 30, 2021	117,439	$ 28	481,390	(69)	(363,737)	(173)
Ending balance, Shares at Sep. 30, 2021		27,790,677
Beginning balance at Mar. 31, 2021	49,532	$ 16	395,422	(57)	(345,679)	(170)
Begining balance, Shares at Mar. 31, 2021		16,011,385
Issuance of common stock upon exercise of stock options	1		1
Issuance of common stock upon exercise of stock options, shares		553
Issuance of common stock pursuant to employee stock purchase plan	5		5
Issuance of common stock pursuant to employee stock purchase plan, shares		1,602
Issuance of common stock from at-the-market offerings, net of offering costs	1,265		1,265
Issuance of common stock from at the market offerings, net of offering costs, shares		293,830
Stock-based compensation	398		398
Net unrealized loss on investments, net of tax	(4)			(4)
Net loss	(10,392)				(10,391)	(1)
Ending balance at Jun. 30, 2021	40,805	$ 16	397,091	(61)	(356,070)	(171)
Ending balance, Shares at Jun. 30, 2021		16,307,370
Issuance of common stock upon exercise of stock options	58		58
Issuance of common stock upon exercise of stock options, shares		9,620
Issuance of common stock from at-the-market offerings, net of offering costs	3,184	$ 1	3,183
Issuance of common stock from at the market offerings, net of offering costs, shares		692,437
Issuance of common stock from underwritten follow-on offering, net of offering costs	80,627	$ 11	80,616
Issuance of common stock from underwritten follow-on offering, net of offering costs, Shares		10,781,250
Stock-based compensation	442		442
Net unrealized loss on investments, net of tax	(8)			(8)
Net loss	(7,669)				(7,667)	(2)
Ending balance at Sep. 30, 2021	117,439	$ 28	481,390	(69)	(363,737)	(173)
Ending balance, Shares at Sep. 30, 2021		27,790,677
Beginning balance at Dec. 31, 2021	109,126	$ 28	481,832	(263)	(372,296)	(175)
Begining balance, Shares at Dec. 31, 2021		27,793,035
Issuance of common stock upon release of restricted stock units, shares		2,500
Issuance of common stock upon exercise of stock options	1		1
Issuance of common stock upon exercise of stock options, shares		259
Issuance of common stock from at-the-market offerings, net of offering costs	1,480		1,480
Issuance of common stock from at the market offerings, net of offering costs, shares		260,455
Stock-based compensation	417		417
Net unrealized loss on investments, net of tax	(496)			(496)
Net loss	(12,154)				(12,153)	(1)
Ending balance at Mar. 31, 2022	98,374	$ 28	483,730	(759)	(384,449)	(176)
Ending balance, Shares at Mar. 31, 2022		28,056,249
Beginning balance at Dec. 31, 2021	$ 109,126	$ 28	481,832	(263)	(372,296)	(175)
Begining balance, Shares at Dec. 31, 2021		27,793,035
Issuance of common stock upon exercise of stock options, shares	259
Net unrealized loss on investments, net of tax	$ (406)
Net loss	(37,820)
Ending balance at Sep. 30, 2022	77,006	$ 29	487,937	(669)	(410,113)	(178)
Ending balance, Shares at Sep. 30, 2022		29,009,382
Beginning balance at Mar. 31, 2022	98,374	$ 28	483,730	(759)	(384,449)	(176)
Begining balance, Shares at Mar. 31, 2022		28,056,249
Issuance of common stock pursuant to employee stock purchase plan	5		5
Issuance of common stock pursuant to employee stock purchase plan, shares		1,958
Issuance of common stock from at-the-market offerings, net of offering costs	34		34
Issuance of common stock from at the market offerings, net of offering costs, shares		69,251
Stock-based compensation	517		517
Net unrealized loss on investments, net of tax	(51)			(51)
Net loss	(12,421)				(12,420)	(1)
Ending balance at Jun. 30, 2022	86,458	$ 28	484,286	(810)	(396,869)	(177)
Ending balance, Shares at Jun. 30, 2022		28,127,458
Issuance of common stock from at-the-market offerings, net of offering costs	3,037	$ 1	3,036
Issuance of common stock from at the market offerings, net of offering costs, shares		881,924
Stock-based compensation	615		615
Net unrealized loss on investments, net of tax	141			141
Net loss	(13,245)				(13,244)	(1)
Ending balance at Sep. 30, 2022	$ 77,006	$ 29	$ 487,937	$ (669)	$ (410,113)	$ (178)
Ending balance, Shares at Sep. 30, 2022		29,009,382

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows (Unaudited) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2022 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)
Cash flows from operating activities:
Consolidated net loss	$ (13,245)	$ (37,820)	$ (25,216)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization		193	367
Stock-based compensation	615	1,549	1,200
Amortization of premium of available-for-sale investment securities		565	143
Amortization of right-of-use assets		805	617
Gain on disposal of property and equipment		(95)
Changes in operating assets and liabilities:
Other receivables		70	1,910
Prepaid expenses and other assets		(1,174)	(3,244)
Accounts payable and accrued expenses		4,878	(133)
Operating lease liability		(488)	(633)
Net cash used in operating activities		(31,517)	(24,989)
Cash flows from investing activities:
Purchases of property and equipment		(522)	(174)
Purchases of available-for-sale investment securities		(17,124)	(68,811)
Maturities of available-for-sale investment securities		62,713	26,767
Proceeds from sale of property and equipment		179
Net cash provided by (used in) investing activities		45,246	(42,218)
Cash flows from financing activities:
Proceeds from issuance of common stock through option exercises		1	59
Proceeds from issuance of common stock through employee stock purchase plan		5	5
Proceeds from issuance of common stock from at-the-market offerings, net of offering costs		4,551	14,070
Proceeds from issuance of common stock from committed purchase agreement, net of offering costs			15,236
Proceeds from issuance of common stock from underwritten follow-on offering, net of offering costs			80,627
Principal paid on finance lease liabilities		(24)
Net cash provided by financing activities		4,533	109,997
Net change in cash, cash equivalents and restricted cash		18,262	42,790
Cash, cash equivalents and restricted cash at beginning of period		2,336	16,952
Cash, cash equivalents and restricted cash at the end of period	20,598	20,598	59,742
Cash and cash equivalents at the end of period	18,359	18,359	59,742
Restricted cash at the end of period	2,239	2,239
Cash, cash equivalents and restricted cash at the end of period	$ 20,598	20,598	$ 59,742
Supplemental schedule of noncash investing and financing activities:
Purchases of property and equipment in accounts payable		487
Right-of-use assets obtained in exchange for lease obligation		$ 800

Organization, Business, Basis o

Organization, Business, Basis of Presentation and Summary of Significant Accounting Policies	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Organization, Business, Basis of Presentation and Summary of Significant Accounting Policies	1. Organization, Business, Basis of Presentation and Summary of Significant Accounting Policies Organization and Business aTyr Pharma, Inc. (we, us, and our) was incorporated in the State of Delaware on September 8, 2005. We are a biotherapeutics company engaged in the discovery and development of first-in-class medicines from our proprietary tRNA synthetase platform. Principles of Consolidation Our condensed consolidated financial statements include our accounts and our 98 % majority-owned subsidiary in Hong Kong, Pangu BioPharma Limited (Pangu BioPharma). All intercompany transactions and balances are eliminated in consolidation. Unaudited Interim Financial Information The accompanying interim unaudited condensed consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (U.S. GAAP) and follow the requirements of the U.S. Securities and Exchange Commission (SEC) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. In our opinion, the interim unaudited condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and include all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of our financial position and our results of operations and cash flows for the periods presented. These statements do not include all disclosures required by U.S. GAAP and should be read in conjunction with our audited consolidated financial statements and accompanying notes contained in our Annual Report on Form 10-K for the fiscal year ended December 31, 2021, as filed with the SEC on March 15, 2022. The results of the interim periods are not necessarily indicative of the results expected for the full fiscal year or any other interim period or any future year or period. Risks and Uncertainties The impact of the ongoing COVID-19 pandemic has been and will likely continue to be extensive in many aspects of society, which has resulted in and will likely continue to result in significant disruptions to the global economy, as well as businesses and capital markets around the world. Impacts to our business have included delayed enrollment of our now completed Phase 1b/2a clinical trial in patients with pulmonary sarcoidosis and the discontinuation of some patients in that trial, temporary closures of portions of our facilities and those of our licensees and collaborators, disruptions or restrictions on our employee’s ability to travel and delays in certain research and development activities. Other potential impacts to our business include, but are not limited to, disruptions to or delays in planned clinical trials, third-party manufacturing supply and other operations, inflation, the potential diversion of healthcare resources away from the conduct of clinical trials to focus on pandemic concerns, interruptions or delays in the operations of the U.S. Food and Drug Administration or other regulatory authorities, and our ability to raise capital and conduct business development activities. In addition to the ongoing COVID-19 pandemic, global economic and business activities continue to face widespread macroeconomic uncertainties, including labor shortages, inflation and monetary supply shifts, recession risks and potential disruptions from the Russia-Ukraine conflict, which has resulted in volatility in the U.S. and global financial markets and which has led to, and may continue to lead to, additional disruptions to trade, commerce, pricing stability, credit availability and supply chain continuity globally. It is uncertain what the long-term impact of the ongoing Ukraine-Russia conflict may have on our business and we continue to actively monitor the impact of these macroeconomic factors on our results of operations, financial condition and cash flows. The extent of the impact of these factors on our operational and financial performance, including our ability to execute our business strategies and initiatives in the expected timeframe, will depend on future developments, which are uncertain and cannot be predicted; however, any continued or renewed disruption resulting from these factors could negatively impact our business. Liquidity and Financial Condition We have incurred net losses in each year since our inception in 2005, including a consolidated net loss o f $ 13.2 million and $ 37.8 million for the three and nine months ended September 30, 2022, respectively. As of September 30, 2022, we had an accumulated deficit of $ 410.1 million. We believe that our existing cash, cash equivalents, restricted cash and available-for-sale investments of $ 79.6 million as of September 30, 2022 will be sufficient to meet our material cash requirements from known contractual and other obligations for a period of at least one year from the filing date of this Quarterly Report on Form 10-Q. We do not expect to generate any revenues from product sales unless and until we successfully complete development and obtain regulatory approval for one or more of our product candidates, which we expect will take a number of years at a minimum. If we obtain regulatory approval for any of our product candidates, we expect to incur significant commercialization expenses related to product sales, marketing, manufacturing and distribution. Accordingly, we will need to raise substantial additional capital to fund our operations. The amount and timing of our future funding requirements will depend on many factors, including the pace and results of our preclinical and clinical development efforts and the timing and nature of the regulatory approval process for our product candidates. We anticipate that we will seek to fund our operations through equity offerings, grant funding, collaborations, strategic partnerships and/or licensing arrangements, and when we are closer to commercialization of our product candidates potentially through debt financings. However, we may be unable to raise additional capital or enter into such arrangements when needed on favorable terms or at all. Our failure to raise capital or enter into such arrangements when needed would have a negative impact on our financial condition and ability to develop our product candidates. Restricted Cash As of September 30, 2022, restricted cash consisted of approximately $ 2.2 million, which was held as a security deposit in conjunction with our new facility lease and financing leases as discussed further below in Note 4 – Commitments and Contingencies. Use of Estimates Our unaudited condensed consolidated financial statements are prepared in accordance with U.S. GAAP. The preparation of our unaudited condensed consolidated financial statements requires us to make estimates and assumptions that impact the reported amounts of assets, liabilities and expenses and the disclosure for these items in our unaudited condensed consolidated financial statements and accompanying notes. The most significant estimates in our unaudited condensed consolidated financial statements relate to clinical trial and research and development expenses. Although these estimates are based on our knowledge of current events and actions we may undertake in the future, actual results may ultimately differ materially from these estimates and assumptions. Leases We determine if an arrangement is a lease at inception. Short-term leases with an initial term of 12 months or less are not recorded on our balance sheet. For long-term leases with an initial term of greater than 12 months, we recognize a right-of-use asset (ROU) and a lease liability based on the present value of future lease payments using an estimated rate of interest that we would pay to borrow equivalent funds on a collateralized basis at the lease commencement date. We determine the lease term at the commencement date by considering whether renewal options and termination options are reasonably assured of exercise. Rent expense for operating leases is recognized on a straight-line basis over the lease term and is included in operating expenses in our unaudited condensed consolidated statements of operations. For financing leases, interest expense and amortization of the ROU is included in operating expenses in our unaudited condensed consolidated statements of operations and variable lease payments are recorded as incurred. If a lease is modified, the modified contract is evaluated to determine whether it is or contains a lease. If a lease continues to exist, the lease modification is determined to be a separate contract when the modification grants the lessee an additional ROU that is not included in the original lease and the lease payments increase commensurate with the standalone price for the additional ROU. A lease modification that results in a separate contract will be accounted for in the same manner as a new lease. For a modification that is not a separate contract, we reassess the lease classification using the modified terms and conditions and the facts and circumstances as of the effective date of the modification and recognize the amount of the remeasurement of the lease liability for the modified lease as an adjustment to the corresponding lease ROU asset. Our ROU assets consist of the Lease (as defined below) and the non-cancelable operating lease for our existing office and laboratory space and financing leases for various research and development and information technology equipment. We do not separate lease and non-lease components of our long-term leases. Revenue Recognition We evaluate our agreements under Accounting Standard Codification (ASC) Topic 606, Revenue from Contracts with Customers (Topic 606) and ASC Topic 808, Collaborative Arrangements . We recognize revenue when we transfer promised goods or services to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those goods or services. In determining the appropriate amount of revenue to be recognized as we fulfill our obligations under our agreement, we perform the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) we satisfy each performance obligation. As part of the accounting for these arrangements, we must develop assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. We use key assumptions to determine the stand-alone selling price, which may include forecasted revenues, development timelines, reimbursement rates for personnel costs, discount rates and probabilities of technical and regulatory success. We recognize revenue in one of two ways, over time or at a point in time. We recognize revenue over time when we are executing on our performance obligation over time and our partner receives benefit over time. For example, we recognize revenue over time when we provide research and development services. We recognize revenue at a point in time when we transfer control of a distinct performance obligation to our partner. For example, if a license to our intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, we recognize revenues from non-refundable, up-front fees allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license. Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period. Diluted net loss per share is calculated by dividing the net loss by the weighted-average number of common stock equivalents outstanding for the period determined using the treasury-stock method. Dilutive common stock equivalents are comprised of warrants for common stock, options and restricted stock units outstanding under our stock option plan and estimated shares to be purchased under our employee stock purchase plan. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding, as the assumed exercise or settlement of stock options, restricted stock units, and warrants, or the conversion of preferred stock are anti-dilutive. Potentially dilutive securities not considered for the calculation of diluted net loss per share are as follows (in common stock equivalents): Nine Months Ended September 30, 2022 2021 Common stock warrants 13,760 13,760 Common stock options and restricted stock units 3,082,068 1,279,036 Employee stock purchase plan 19,062 1,780 Total 3,114,890 1,294,576 Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board issued Accounting Standards Update (ASU) No. 2016-13, Financial Instruments – Credit Losses (Topic 326), to provide financial statement users with more decision-useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. To achieve this objective, the amendments in Topic 326 replace the incurred loss impairment methodology in current U.S. GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. Topic 326 is effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years for smaller reporting companies. We do not expect the adoption of the amendments in Topic 326 to have a material effect on our condensed consolidated financial position or results of operations when such amendment is effective.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	2. Fair Value Measurements The carrying amounts of cash equivalents, prepaid and other assets, accounts payable and accrued liabilities are considered to be representative of their respective fair values because of the short-term nature of those instruments. Investment securities are recorded at fair value. The accounting guidance defines fair value, establishes a consistent framework for measuring fair value and expands disclosure for each major asset and liability category measured at fair value on either a recurring or nonrecurring basis. Fair value is defined as an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that should be determined based on assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, the accounting guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows: Level 1: Observable inputs such as quoted prices in active markets. Level 2: Inputs, other than the quoted prices in active markets that are observable either directly or indirectly. Level 3: Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions. Financial assets measured at fair value on a recurring basis consist of investment securities. Investment securities are recorded at fair value, defined as the exit price in the principal market in which we would transact, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. Level 2 securities are valued using quoted market prices for similar instruments, non-binding market prices that are corroborated by observable market data, or discounted cash flow techniques and include our investments in commercial paper, corporate debt securities and asset-backed securities. We have no financial liabilities measured at fair value on a recurring basis. None of our non-financial assets and liabilities are recorded at fair value on a non-recurring basis. No transfers between levels have occurred during the periods presented. Assets measured at fair value on a recurring basis are as follows (in thousands): Fair Value Measurements Using Total Quoted Prices in Markets Identical Significant Significant As of September 30, 2022 Assets: Current: Cash equivalents $ 17,513 $ 17,513 $ — $ — Available-for-sale investments: Commercial paper 15,792 — 15,792 — Corporate debt securities 34,434 — 34,434 — Municipal bonds 8,789 — 8,789 — Total available-for-sale investments 59,015 — 59,015 — Total assets measured at fair value $ 76,528 $ 17,513 $ 59,015 $ — Fair Value Measurements Using Total Quoted Prices in Markets Identical Significant Significant As of December 31, 2021 Assets: Current: Cash equivalents $ 2,052 $ 2,052 $ — $ — Available-for-sale investments: Commercial paper 36,921 — 36,921 — Corporate debt securities 55,713 — 55,713 — Municipal bonds 12,941 — 12,941 — Total available-for-sale investments 105,575 — 105,575 — Total assets measured at fair value $ 107,627 $ 2,052 $ 105,575 $ — As of September 30, 2022 and December 31, 2021, available-for-sale investments are detailed as follows (in thousands): September 30, 2022 Contractual Maturity Gross Gross Gross Market Value Available-for-sale investments: Commercial paper Within 1 year $ 15,871 $ — $ ( 79 ) $ 15,792 Corporate debt securities 1 to 2 years 34,921 — ( 487 ) 34,434 Municipal bonds Within 1 year 8,842 — ( 53 ) 8,789 $ 59,634 $ — $ ( 619 ) $ 59,015 December 31, 2021 Contractual Maturity Gross Gross Gross Market Value Available-for-sale investments: Commercial paper Within 1 year $ 36,956 $ — $ ( 35 ) $ 36,921 Corporate debt securities 1 to 2 years 55,859 — ( 146 ) 55,713 Municipal bonds 1 to 2 years 12,973 — ( 32 ) 12,941 $ 105,788 $ — $ ( 213 ) $ 105,575 At each reporting date, we perform an evaluation of impairment to determine if any unrealized losses are other-than-temporary. Factors considered in determining whether a loss is other-than-temporary include the length of time and extent to which fair value has been less than the cost basis, the financial condition of the issuer, and our intent and ability to hold the investment until recovery of its amortized cost basis. We intend, and have the ability, to hold our investments in unrealized loss positions, if any, until their amortized cost basis has been recovered. As of September 30, 2022, all available-for-sale investments had a variety of effective maturity dates of less than two years . As of September 30, 2022, all available-for-sale investments were in gross unrealized loss positions of which 7 of 26 available-for-sale investments with a market value of $ 13.4 million were at a loss position greater than 12 months .

License and Other Agreements

License and Other Agreements	9 Months Ended
	Sep. 30, 2022
License Agreements [Abstract]
License and Other Agreements	3. License and Other Agreements Kyorin Pharmaceutical Co., Ltd. In January 2020, we entered into a collaboration and license agreement (Kyorin Agreement) with Kyorin Pharmaceutical Co., Ltd. (Kyorin) for the development and commercialization of efzofitimod for interstitial lung disease (ILD) in Japan. Under the Kyorin Agreement, Kyorin received an exclusive right to develop and commercialize efzofitimod in Japan for all forms of ILD. Kyorin is obligated to fund all research, development, regulatory, marketing and commercialization activities in Japan. In 2020, Kyorin completed a Phase 1 clinical trial of efzofitimod (known as KRP-R120 in Japan). The Phase 1 clinical trial, which was conducted and funded by Kyorin, was a placebo-controlled study to evaluate the safety, pharmacokinetics and immunogenicity of efzofitimod in 32 healthy Japanese male volunteers. Efzofitimod was observed to be generally well-tolerated with no drug-related serious adverse events and pharmacokinetics findings were consistent with previous studies of efzofitimod. We received an $ 8.0 million upfront payment in January 2020 and a $ 2.0 million milestone payment in January 2021 following completion of enrollment in the Phase 1 clinical trial. Kyorin has joined our Phase 3 clinical trial of efzofitimod in pulmonary sarcoidosis patients (EFZO-FIT ™ study) , and all study activity in Japan will be funded by Kyorin. We are eligible to receive up to an additional $ 165.0 million in the aggregate upon achievement of certain development, regulatory and sales milestones, as well as tiered royalties ranging from the mid-single digits to mid-teens on net sales in Japan. Either party may terminate the Kyorin Agreement in the event that the other party breaches the agreement and fails to cure the breach, becomes insolvent or challenges certain of the intellectual property rights licensed under the agreement. We assessed our license and collaboration with Kyorin in accordance with Topic 606 and concluded that Kyorin is a customer. We identified the following performance obligations under the Kyorin Agreement: 1) the license of efzofitimod for ILD in Japan; and 2) free clinical trial material for Kyorin’s Phase 1 clinical trial. The $ 8.0 million upfront payment received from Kyorin is non-refundable and non-creditable and is considered fixed consideration. We determined that the relative stand-alone selling price was $ 7.9 million when the license was delivered to Kyorin in January 2020. We determined that the relative standalone selling price was $ 0.1 million for the free clinical trial material delivered to Kyorin in June 2020, using the “expected cost plus a margin” approach. In December 2020, Kyorin completed the last subject visit in its Phase 1 clinical trial of efzofitimod. This achievement triggered a $ 2.0 million milestone payment which we recognized as license and collaboration revenue in December 2020. We received the $ 2.0 million from Kyorin in January 2021. During the three and nine months ended September 30, 2022 and 2021, there were no activities that triggered additional license and collaboration agreement revenue under the Kyorin Agreement. The remaining milestones and royalty payments under the Kyorin Agreement are variable consideration. Since milestone payments are binary in nature, we will use the “most-likely” method to evaluate whether the milestones should be included as revenue. We will constrain these amounts until the milestone is probable of being achieved. The royalties are dependent on future sales by Kyorin which are at the full discretion of Kyorin. Accordingly, we constrain these amounts until the future sales have occurred. Hong Kong University of Science and Technology In March 2020, our subsidiary, Pangu BioPharma, together with the Hong Kong University of Science and Technology (HKUST) was awarded a grant of approximately $ 750,000 to build a high-throughput platform for the development of bi-specific antibodies. The project is being funded by the Hong Kong government’s Innovation and Technology Commission (ITC) under the Partnership Research Program (PRP). The PRP aims to support research and development projects undertaken by companies in collaboration with local universities and public research institutions. The ITC funded approximately 50% of the total estimated project cost and we contributed the remaining 50%. The research grant agreement between Pangu BioPharma, HKUST and the Government of the Hong Kong Special Administration Region became effective April 1, 2020 . In May 2021, we announced that Pangu BioPharma and HKUST achieved certain milestones for the first year of the project. The project was completed as of September 30, 2022. All the contributions provided by the ITC are paid to HKUST and we record expenses under this grant award when incurred. Expenses for the three months ended September 30, 2022 and 2021 were $ 27,000 and $ 0.1 million, respectively. Expenses for the nine months ended September 30, 2022 and 2021 were $ 0.1 million and $ 0.3 million, respectively.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2022
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	4. Commitments and Contingencies Operating Leases We have a non-cancelable facility lease that is subject to base lease payments, which escalate over the term of the lease, additional charges for common area maintenance and other costs. In July 2018, we entered into a lease amendment that reduced the space we lease from 24,494 square feet to 20,508 square feet and extended the lease term to May 2023 . With the lease amendment, we do not have an option to extend the lease. In May 2022, we entered into a lease (the Lease) with San Diego Creekside, LLC (Landlord), as lessor, pursuant to which we agreed to lease from Landlord approximately 23,696 rentable square feet (subject to increase pursuant to the terms of the Lease) of office and laboratory space. The term of the lease (the Lease Term) will commence upon the earlier of April 1, 2023 or the completion of certain leasehold improvements to the Premises (as defined in the Lease), but not sooner than March 1, 2023 (the Lease Commencement Date) and continue for 124 months from the Lease Commencement Date. We also have one option to extend the Lease Term for five years . Base rent during such extension period would be at the fair market rent for the Premises. Under the terms of the Lease, the base rent during the first 12 months of the Lease Term will be $ 5.75 per square foot of rentable area per month, subject to certain upward adjustments of approximately 3.0 % annually. We are entitled to an allowance of $ 5.5 million for tenant improvements, including an option to utilize an additional allowance of up to $ 0.6 million, which, if used by us, would be repaid by us as additional monthly base rent, amortized at eight percent ( 8.0 %) per annum during the Lease Term. We provided a $ 0.7 million security deposit in the form of a letter of credit which is included in restricted cash as of September 30, 2022. Future minimum payments under the Lease and the non-cancelable operating lease for our existing office and laboratory space and reconciliation to the operating lease liability as of September 30, 2022 were as follows (in thousands): Operating Lease 2022 $ 270 2023 1,085 2024 1,675 2025 1,726 2026 1,777 2027 and thereafter 12,933 Less: Amount representing interest ( 7,019 ) Present value of lease payments 12,447 Less: Current portion of operating lease liability ( 657 ) Less: Tenant improvement allowance not yet received ( 4,572 ) Long-term operating lease liability, net of current portion $ 7,218 For each of the three months ended September 30, 2022 and 2021, we recorded an operating lease cost of $ 0.3 million and $ 0.2 million, respectively. For each of the nine months ended September 30, 2022 and 2021, we recorded an operating lease cost of $ 0.8 million and $ 0.7 million, respectively. As of September 30, 2022, the weighted-average remaining lease term was 10.4 years and the weighted-average discount rate was 8.8 %. Financing Leases In April 2022, we entered into a master financing lease agreement to lease various research and development and information technology equipment over a 48-month term. Future minimum payments under the non-cancelable financing lease and reconciliation to the financing lease liability as of September 30, 2022 were as follows (in thousands): Financing Lease 2022 $ 52 2023 208 2024 208 2025 208 2026 223 Less: Amount representing interest ( 123 ) Present value of lease payments 776 Less: Current portion of financing lease liability ( 158 ) Long-term financing lease liability, net of current portion $ 618 As of September 30, 2022, the weighted-average remaining lease term was 3.8 years and the weighted-average discount rate was 7.2 %. We provided a $ 1.5 million deposit to be held as collateral for the leased equipment, and this deposit is included in restricted cash as of September 30, 2022.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2022
Equity [Abstract]
Stockholders' Equity	5. Stockholders’ Equity Underwritten Follow-On Public Offerings In September 2021, we completed an underwritten follow-on public offering of 10,781,250 shares of our common stock, including the full exercise of the underwriters’ option to purchase additional shares, at a price to the public of $ 8.00 per share. The total net proceeds from the offering were approximately $ 80.6 million after deducting underwriting discounts, commissions and offering expenses payable by us. At the Market Offering Programs In March 2021, we entered into a Capital on Demand TM Sales Agreement with JonesTrading Institutional Services LLC (JonesTrading) for an at-the-market offering program (the Prior ATM Offering Program), pursuant to which we were entitled to sell from time to time, at our option, up to an aggregate of $ 25.0 million of shares of our common stock through JonesTrading, as sales agent or principal. JonesTrading was entitled to a commission at a fixed rate of up to 3.0 % of the gross proceeds. During 2021, we sold an aggregate of 986,267 shares of common stock at a weighted-average price of $ 4.75 per share for net proceeds of $ 4.4 million under the Prior ATM Offering Program. During the nine months ended September 30, 2022, we sold an aggregate of 260,455 shares of common stock at a weighted-average price of $ 6.07 per share for net proceeds of approximately $ 1.5 million under the Prior ATM Offering Program. In April 2022, we terminated the Prior ATM Offering Program. In April 2022, we entered into an Open Market Sale Agreement SM with Jefferies LLC (Jefferies) implementing an “at-the-market” offering program (the ATM Offering Program), pursuant to which we may offer and sell, from time to time and at our option, up to an aggregate of $ 65.0 million of shares of our common stock through Jefferies, acting as sales agent. Jefferies is entitled to a fixed commission rate of up to 3.0 % of the gross sales proceeds of shares sold under the ATM Offering Program. During the nine months ended September 30, 2022, we sold an aggregate of 951,175 shares of common stock at a weighted-average price of $ 3.55 per share for net proceeds of approximately $ 3.1 million under the ATM Offering Program. Purchase Agreement In September 2020 , we entered into a common stock purchase agreement (the Purchase Agreement) with Aspire Capital Fund, LLC (Aspire Capital), which provides that, upon the terms and subject to the conditions and limitations set forth therein, Aspire Capital is committed to purchase up to an aggregate of $ 20.0 million of shares of our common stock at our request from time to time during the 30 month term of the Purchase Agreement. Concurrently with entering into the Purchase Agreement, we also entered into a registration rights agreement with Aspire Capital, in which we agreed to file one or more registration statements, as permissible and necessary to register under the Securities Act of 1933, as amended, for the resale of the shares of our common stock that have been and may be issued to Aspire Capital under the Purchase Agreement. During the nine months ended September 30, 2021, we sold an aggregate of 3,000,000 shares of common stock at a weighted-average price of $ 5.09 per share for net proceeds of $ 15.2 million under the Purchase Agreement. During the nine months ended September 30, 2022, there were no issuances or sales under the Purchase Agreement. Inducement Grants In March 2022, we adopted and our board of directors approved our 2022 Inducement Plan (our Inducement Plan). Awards granted under our Inducement Plan are in accordance with Nasdaq Listing Rule 5635(c)(4). A total of 300,000 shares of our common stock were initially reserved for the issuance under our Inducement Plan. The maximum term of options granted under our Inducement Plan is ten years . Each option vests over a period of four years , with 25 % of the shares vesting on the one-year anniversary of the applicable vesting commencement date and the remaining 75 % vesting in equal monthly installments over three years , subject to continuous employment. During the nine months ended September 30, 2022, we granted nonstatutory stock options under our Inducement Plan to purchase an aggregate of 192,400 shares of our common stock, with a weighted-average exercise price of $ 4.04 per share as inducement awards to new employees. Common Stock Reserved for Future Issuance Common stock reserved for future issuance was as follows: September 30, 2022 Common stock warrants 13,760 Common stock options and restricted stock units 3,082,068 Shares available under the 2015 equity incentive plan 948,519 Shares available under the 2022 inducement plan 107,600 Shares available under the employee stock purchase plan 819,975 4,971,922 The following table summarizes our stock option activity under all equity incentive plans for the nine months ended September 30, 2022: Number of Weighted- Outstanding as of December 31, 2021 1,412,550 $ 12.01 Granted 1,573,844 $ 3.44 Exercises ( 259 ) $ 3.77 Canceled/forfeited/expired ( 25,505 ) $ 12.27 Outstanding as of September 30, 2022 2,960,630 $ 7.45 The assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee stock option grants were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Expected term (in years) 5.98 – 6.06 5.98 – 6.06 5.98 – 6.08 5.50 – 6.08 Risk-free interest rate 2.7 %- 2.9 % 0.8 % – 1.1 % 1.7 % – 3.0 % 0.6 % – 1.1 % Expected volatility 84.5 % – 84.6 % 86.3 % – 86.9 % 84.5 % – 86.5 % 86.3 % – 104.8 % Expected dividend yield 0.0 % 0.0 % 0.0 % 0.0 % The following table summarizes our restricted stock unit activity under all equity incentive plans for the nine months ended September 30, 2022: Number of Outstanding Weighted-Average Balance as of December 31, 2021 7,500 $ 4.08 Granted 116,438 $ 5.13 Released ( 2,500 ) $ 4.13 Balance as of September 30, 2022 121,438 $ 5.09 Stock-based Compensation The allocation of stock-based compensation for all options and restricted stock units and stock issued pursuant to our employee stock purchase plan is as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Research and development $ 150 $ 70 $ 388 $ 198 General and administrative 465 372 1,161 1,002 Total stock-based compensation expense $ 615 $ 442 $ 1,549 $ 1,200

Organization, Business, Basis_2

Organization, Business, Basis of Presentation and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Organization and Business	Organization and Business aTyr Pharma, Inc. (we, us, and our) was incorporated in the State of Delaware on September 8, 2005. We are a biotherapeutics company engaged in the discovery and development of first-in-class medicines from our proprietary tRNA synthetase platform.
Principles of Consolidation	Principles of Consolidation Our condensed consolidated financial statements include our accounts and our 98 % majority-owned subsidiary in Hong Kong, Pangu BioPharma Limited (Pangu BioPharma). All intercompany transactions and balances are eliminated in consolidation.
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying interim unaudited condensed consolidated financial statements have been prepared in accordance with United States generally accepted accounting principles (U.S. GAAP) and follow the requirements of the U.S. Securities and Exchange Commission (SEC) for interim reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by U.S. GAAP can be condensed or omitted. In our opinion, the interim unaudited condensed consolidated financial statements have been prepared on the same basis as the audited consolidated financial statements and include all adjustments, which include only normal recurring adjustments, necessary for the fair presentation of our financial position and our results of operations and cash flows for the periods presented. These statements do not include all disclosures required by U.S. GAAP and should be read in conjunction with our audited consolidated financial statements and accompanying notes contained in our Annual Report on Form 10-K for the fiscal year ended December 31, 2021, as filed with the SEC on March 15, 2022. The results of the interim periods are not necessarily indicative of the results expected for the full fiscal year or any other interim period or any future year or period.
Risks and Uncertainties	Risks and Uncertainties The impact of the ongoing COVID-19 pandemic has been and will likely continue to be extensive in many aspects of society, which has resulted in and will likely continue to result in significant disruptions to the global economy, as well as businesses and capital markets around the world. Impacts to our business have included delayed enrollment of our now completed Phase 1b/2a clinical trial in patients with pulmonary sarcoidosis and the discontinuation of some patients in that trial, temporary closures of portions of our facilities and those of our licensees and collaborators, disruptions or restrictions on our employee’s ability to travel and delays in certain research and development activities. Other potential impacts to our business include, but are not limited to, disruptions to or delays in planned clinical trials, third-party manufacturing supply and other operations, inflation, the potential diversion of healthcare resources away from the conduct of clinical trials to focus on pandemic concerns, interruptions or delays in the operations of the U.S. Food and Drug Administration or other regulatory authorities, and our ability to raise capital and conduct business development activities. In addition to the ongoing COVID-19 pandemic, global economic and business activities continue to face widespread macroeconomic uncertainties, including labor shortages, inflation and monetary supply shifts, recession risks and potential disruptions from the Russia-Ukraine conflict, which has resulted in volatility in the U.S. and global financial markets and which has led to, and may continue to lead to, additional disruptions to trade, commerce, pricing stability, credit availability and supply chain continuity globally. It is uncertain what the long-term impact of the ongoing Ukraine-Russia conflict may have on our business and we continue to actively monitor the impact of these macroeconomic factors on our results of operations, financial condition and cash flows. The extent of the impact of these factors on our operational and financial performance, including our ability to execute our business strategies and initiatives in the expected timeframe, will depend on future developments, which are uncertain and cannot be predicted; however, any continued or renewed disruption resulting from these factors could negatively impact our business.
Liquidity and Financial Condition	Liquidity and Financial Condition We have incurred net losses in each year since our inception in 2005, including a consolidated net loss o f $ 13.2 million and $ 37.8 million for the three and nine months ended September 30, 2022, respectively. As of September 30, 2022, we had an accumulated deficit of $ 410.1 million. We believe that our existing cash, cash equivalents, restricted cash and available-for-sale investments of $ 79.6 million as of September 30, 2022 will be sufficient to meet our material cash requirements from known contractual and other obligations for a period of at least one year from the filing date of this Quarterly Report on Form 10-Q. We do not expect to generate any revenues from product sales unless and until we successfully complete development and obtain regulatory approval for one or more of our product candidates, which we expect will take a number of years at a minimum. If we obtain regulatory approval for any of our product candidates, we expect to incur significant commercialization expenses related to product sales, marketing, manufacturing and distribution. Accordingly, we will need to raise substantial additional capital to fund our operations. The amount and timing of our future funding requirements will depend on many factors, including the pace and results of our preclinical and clinical development efforts and the timing and nature of the regulatory approval process for our product candidates. We anticipate that we will seek to fund our operations through equity offerings, grant funding, collaborations, strategic partnerships and/or licensing arrangements, and when we are closer to commercialization of our product candidates potentially through debt financings. However, we may be unable to raise additional capital or enter into such arrangements when needed on favorable terms or at all. Our failure to raise capital or enter into such arrangements when needed would have a negative impact on our financial condition and ability to develop our product candidates.
Restricted Cash	Restricted Cash As of September 30, 2022, restricted cash consisted of approximately $ 2.2 million, which was held as a security deposit in conjunction with our new facility lease and financing leases as discussed further below in Note 4 – Commitments and Contingencies.
Use of Estimates	Use of Estimates Our unaudited condensed consolidated financial statements are prepared in accordance with U.S. GAAP. The preparation of our unaudited condensed consolidated financial statements requires us to make estimates and assumptions that impact the reported amounts of assets, liabilities and expenses and the disclosure for these items in our unaudited condensed consolidated financial statements and accompanying notes. The most significant estimates in our unaudited condensed consolidated financial statements relate to clinical trial and research and development expenses. Although these estimates are based on our knowledge of current events and actions we may undertake in the future, actual results may ultimately differ materially from these estimates and assumptions.
Leases	Leases We determine if an arrangement is a lease at inception. Short-term leases with an initial term of 12 months or less are not recorded on our balance sheet. For long-term leases with an initial term of greater than 12 months, we recognize a right-of-use asset (ROU) and a lease liability based on the present value of future lease payments using an estimated rate of interest that we would pay to borrow equivalent funds on a collateralized basis at the lease commencement date. We determine the lease term at the commencement date by considering whether renewal options and termination options are reasonably assured of exercise. Rent expense for operating leases is recognized on a straight-line basis over the lease term and is included in operating expenses in our unaudited condensed consolidated statements of operations. For financing leases, interest expense and amortization of the ROU is included in operating expenses in our unaudited condensed consolidated statements of operations and variable lease payments are recorded as incurred. If a lease is modified, the modified contract is evaluated to determine whether it is or contains a lease. If a lease continues to exist, the lease modification is determined to be a separate contract when the modification grants the lessee an additional ROU that is not included in the original lease and the lease payments increase commensurate with the standalone price for the additional ROU. A lease modification that results in a separate contract will be accounted for in the same manner as a new lease. For a modification that is not a separate contract, we reassess the lease classification using the modified terms and conditions and the facts and circumstances as of the effective date of the modification and recognize the amount of the remeasurement of the lease liability for the modified lease as an adjustment to the corresponding lease ROU asset. Our ROU assets consist of the Lease (as defined below) and the non-cancelable operating lease for our existing office and laboratory space and financing leases for various research and development and information technology equipment. We do not separate lease and non-lease components of our long-term leases.
Revenue Recognition	Revenue Recognition We evaluate our agreements under Accounting Standard Codification (ASC) Topic 606, Revenue from Contracts with Customers (Topic 606) and ASC Topic 808, Collaborative Arrangements . We recognize revenue when we transfer promised goods or services to customers in an amount that reflects the consideration to which we expect to be entitled in exchange for those goods or services. In determining the appropriate amount of revenue to be recognized as we fulfill our obligations under our agreement, we perform the following steps: (i) identification of the promised goods or services in the contract; (ii) determination of whether the promised goods or services are performance obligations including whether they are distinct in the context of the contract; (iii) measurement of the transaction price, including the constraint on variable consideration; (iv) allocation of the transaction price to the performance obligations; and (v) recognition of revenue when (or as) we satisfy each performance obligation. As part of the accounting for these arrangements, we must develop assumptions that require judgment to determine the stand-alone selling price for each performance obligation identified in the contract. We use key assumptions to determine the stand-alone selling price, which may include forecasted revenues, development timelines, reimbursement rates for personnel costs, discount rates and probabilities of technical and regulatory success. We recognize revenue in one of two ways, over time or at a point in time. We recognize revenue over time when we are executing on our performance obligation over time and our partner receives benefit over time. For example, we recognize revenue over time when we provide research and development services. We recognize revenue at a point in time when we transfer control of a distinct performance obligation to our partner. For example, if a license to our intellectual property is determined to be distinct from the other performance obligations identified in the arrangement, we recognize revenues from non-refundable, up-front fees allocated to the license when the license is transferred to the licensee and the licensee is able to use and benefit from the license.
Net Loss Per Share	Net Loss Per Share Basic net loss per share is calculated by dividing the net loss by the weighted-average number of common shares outstanding for the period. Diluted net loss per share is calculated by dividing the net loss by the weighted-average number of common stock equivalents outstanding for the period determined using the treasury-stock method. Dilutive common stock equivalents are comprised of warrants for common stock, options and restricted stock units outstanding under our stock option plan and estimated shares to be purchased under our employee stock purchase plan. For all periods presented, there is no difference in the number of shares used to calculate basic and diluted shares outstanding, as the assumed exercise or settlement of stock options, restricted stock units, and warrants, or the conversion of preferred stock are anti-dilutive. Potentially dilutive securities not considered for the calculation of diluted net loss per share are as follows (in common stock equivalents): Nine Months Ended September 30, 2022 2021 Common stock warrants 13,760 13,760 Common stock options and restricted stock units 3,082,068 1,279,036 Employee stock purchase plan 19,062 1,780 Total 3,114,890 1,294,576
Recent Accounting Pronouncements	Recent Accounting Pronouncements In June 2016, the Financial Accounting Standards Board issued Accounting Standards Update (ASU) No. 2016-13, Financial Instruments – Credit Losses (Topic 326), to provide financial statement users with more decision-useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. To achieve this objective, the amendments in Topic 326 replace the incurred loss impairment methodology in current U.S. GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. Topic 326 is effective for fiscal years beginning after December 15, 2022, including interim periods within those fiscal years for smaller reporting companies. We do not expect the adoption of the amendments in Topic 326 to have a material effect on our condensed consolidated financial position or results of operations when such amendment is effective.

Organization, Business, Basis_3

Organization, Business, Basis of Presentation and Summary of Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2022
Accounting Policies [Abstract]
Schedule of Potentially Dilutive Securities Not Considered for Calculation of Diluted Net Loss Per Share	Potentially dilutive securities not considered for the calculation of diluted net loss per share are as follows (in common stock equivalents): Nine Months Ended September 30, 2022 2021 Common stock warrants 13,760 13,760 Common stock options and restricted stock units 3,082,068 1,279,036 Employee stock purchase plan 19,062 1,780 Total 3,114,890 1,294,576

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2022
Fair Value Disclosures [Abstract]
Schedule of Assets Measured at Fair Value on Recurring Basis	Assets measured at fair value on a recurring basis are as follows (in thousands): Fair Value Measurements Using Total Quoted Prices in Markets Identical Significant Significant As of September 30, 2022 Assets: Current: Cash equivalents $ 17,513 $ 17,513 $ — $ — Available-for-sale investments: Commercial paper 15,792 — 15,792 — Corporate debt securities 34,434 — 34,434 — Municipal bonds 8,789 — 8,789 — Total available-for-sale investments 59,015 — 59,015 — Total assets measured at fair value $ 76,528 $ 17,513 $ 59,015 $ — Fair Value Measurements Using Total Quoted Prices in Markets Identical Significant Significant As of December 31, 2021 Assets: Current: Cash equivalents $ 2,052 $ 2,052 $ — $ — Available-for-sale investments: Commercial paper 36,921 — 36,921 — Corporate debt securities 55,713 — 55,713 — Municipal bonds 12,941 — 12,941 — Total available-for-sale investments 105,575 — 105,575 — Total assets measured at fair value $ 107,627 $ 2,052 $ 105,575 $ —
Schedule of Available-for-sale Investments	As of September 30, 2022 and December 31, 2021, available-for-sale investments are detailed as follows (in thousands): September 30, 2022 Contractual Maturity Gross Gross Gross Market Value Available-for-sale investments: Commercial paper Within 1 year $ 15,871 $ — $ ( 79 ) $ 15,792 Corporate debt securities 1 to 2 years 34,921 — ( 487 ) 34,434 Municipal bonds Within 1 year 8,842 — ( 53 ) 8,789 $ 59,634 $ — $ ( 619 ) $ 59,015 December 31, 2021 Contractual Maturity Gross Gross Gross Market Value Available-for-sale investments: Commercial paper Within 1 year $ 36,956 $ — $ ( 35 ) $ 36,921 Corporate debt securities 1 to 2 years 55,859 — ( 146 ) 55,713 Municipal bonds 1 to 2 years 12,973 — ( 32 ) 12,941 $ 105,788 $ — $ ( 213 ) $ 105,575

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2022
Debt Instruments [Abstract]
Schedule of Future Minimum Payments under Non-cancelable Operating Lease and Reconciliation to Operating Lease Liability	Future minimum payments under the Lease and the non-cancelable operating lease for our existing office and laboratory space and reconciliation to the operating lease liability as of September 30, 2022 were as follows (in thousands): Operating Lease 2022 $ 270 2023 1,085 2024 1,675 2025 1,726 2026 1,777 2027 and thereafter 12,933 Less: Amount representing interest ( 7,019 ) Present value of lease payments 12,447 Less: Current portion of operating lease liability ( 657 ) Less: Tenant improvement allowance not yet received ( 4,572 ) Long-term operating lease liability, net of current portion $ 7,218
Schedule of Future Minimum Payments under Non-cancelable Financing Lease and Reconciliation to Financing Lease Liability	Future minimum payments under the non-cancelable financing lease and reconciliation to the financing lease liability as of September 30, 2022 were as follows (in thousands): Financing Lease 2022 $ 52 2023 208 2024 208 2025 208 2026 223 Less: Amount representing interest ( 123 ) Present value of lease payments 776 Less: Current portion of financing lease liability ( 158 ) Long-term financing lease liability, net of current portion $ 618

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2022
Summary of Common Stock Reserved for Future Issuance	Common stock reserved for future issuance was as follows: September 30, 2022 Common stock warrants 13,760 Common stock options and restricted stock units 3,082,068 Shares available under the 2015 equity incentive plan 948,519 Shares available under the 2022 inducement plan 107,600 Shares available under the employee stock purchase plan 819,975 4,971,922
Summary of Stock Option Activity	The following table summarizes our stock option activity under all equity incentive plans for the nine months ended September 30, 2022: Number of Weighted- Outstanding as of December 31, 2021 1,412,550 $ 12.01 Granted 1,573,844 $ 3.44 Exercises ( 259 ) $ 3.77 Canceled/forfeited/expired ( 25,505 ) $ 12.27 Outstanding as of September 30, 2022 2,960,630 $ 7.45
Schedule of Restricted Stock Unit Activity	The following table summarizes our restricted stock unit activity under all equity incentive plans for the nine months ended September 30, 2022: Number of Outstanding Weighted-Average Balance as of December 31, 2021 7,500 $ 4.08 Granted 116,438 $ 5.13 Released ( 2,500 ) $ 4.13 Balance as of September 30, 2022 121,438 $ 5.09
Schedule of Allocation of Stock-Based Compensation for All Options and Restricted Stock Units and Stock Issued Pursuant to Our Employee Stock Purchase Plan	The allocation of stock-based compensation for all options and restricted stock units and stock issued pursuant to our employee stock purchase plan is as follows (in thousands): Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Research and development $ 150 $ 70 $ 388 $ 198 General and administrative 465 372 1,161 1,002 Total stock-based compensation expense $ 615 $ 442 $ 1,549 $ 1,200
Employee Stock Option [Member]
Summary of Assumptions Used to Determine Fair Value of Employee Stock Option Grants and Performance Options with Market Condition	The assumptions used in the Black-Scholes option pricing model to determine the fair value of the employee stock option grants were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2022 2021 2022 2021 Expected term (in years) 5.98 – 6.06 5.98 – 6.06 5.98 – 6.08 5.50 – 6.08 Risk-free interest rate 2.7 %- 2.9 % 0.8 % – 1.1 % 1.7 % – 3.0 % 0.6 % – 1.1 % Expected volatility 84.5 % – 84.6 % 86.3 % – 86.9 % 84.5 % – 86.5 % 86.3 % – 104.8 % Expected dividend yield 0.0 % 0.0 % 0.0 % 0.0 %

Organization, Business, Basis_4

Organization, Business, Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Significant Accounting Policies [Line Items]
Net loss	$ (13,244)	$ (7,667)	$ (37,817)	$ (25,209)
Accumulated deficit	(410,113)		(410,113)		$ (372,296)
Cash, cash equivalents, restricted cash and available-for-sale investments	79,600		79,600
Restricted cash	$ 2,239		$ 2,239
Pangu BioPharma [Member] | Hong Kong [Member]
Significant Accounting Policies [Line Items]
Majority-owned subsidiary percentage	98%		98%

Organization, Business, Basis_5

Organization, Business, Basis of Presentation and Summary of Significant Accounting Policies - Schedule of Potentially Dilutive Securities Not Considered for Calculation of Diluted Net Loss Per Share (Detail) - shares	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not considered for calculation of diluted net loss per share	3,114,890	1,294,576
Common Stock Warrants [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not considered for calculation of diluted net loss per share	13,760	13,760
Common Stock Options and Restricted Stock Units [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not considered for calculation of diluted net loss per share	3,082,068	1,279,036
Employee Stock Purchase Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Anti-dilutive securities not considered for calculation of diluted net loss per share	19,062	1,780

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets Measured at Fair Value on Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	$ 17,513	$ 2,052
Total assets measured at fair value	76,528	107,627
Available-for-sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	59,015	105,575
Available-for-sale [Member] | Short-term Investments | Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	15,792	36,921
Available-for-sale [Member] | Short-term Investments | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	34,434	55,713
Available-for-sale [Member] | Short-term Investments | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	8,789	12,941
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	17,513	2,052
Total assets measured at fair value	17,513	2,052
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets measured at fair value	59,015	105,575
Significant Other Observable Inputs (Level 2) [Member] | Available-for-sale [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	59,015	105,575
Significant Other Observable Inputs (Level 2) [Member] | Available-for-sale [Member] | Short-term Investments | Commercial Paper [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	15,792	36,921
Significant Other Observable Inputs (Level 2) [Member] | Available-for-sale [Member] | Short-term Investments | Corporate Debt Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	34,434	55,713
Significant Other Observable Inputs (Level 2) [Member] | Available-for-sale [Member] | Short-term Investments | Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value	$ 8,789	$ 12,941

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Available-for-sale Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost	$ 59,634	$ 105,788
Gross Unrealized Losses	(619)	(213)
Market Value	59,015	105,575
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost	15,871	36,956
Gross Unrealized Losses	(79)	(35)
Market Value	15,792	36,921
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost	8,842	12,973
Gross Unrealized Losses	(53)	(32)
Market Value	8,789	12,941
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Amortized Cost	34,921	55,859
Gross Unrealized Losses	(487)	(146)
Market Value	$ 34,434	$ 55,713

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2022 USD ($) Position
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, investments in unrealized loss positions, greater than 12 months	7
Available-for-sale, investments in unrealized loss positions, number of positions	26
Available-for-sale, investments in unrealized loss positions, greater than twelve months, market value | $	$ 13.4
Maximum [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments effective maturity period	2 years
Minimum [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments gross unrealized loss positions, period	12 months

License and Other Agreements -

License and Other Agreements - Additional Information (Detail) - USD ($)	1 Months Ended				3 Months Ended		9 Months Ended
	Jan. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jan. 31, 2020	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Research And Development Arrangement Contract To Perform For Others [Line Items]
Upfront payment received				$ 8,000,000
Milestone payments received	$ 2,000,000
Hong Kong University of Science and Technology [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Collaborative agreement, funding received			$ 750,000
Funding of project cost, description			The ITC funded approximately 50% of the total estimated project cost and we contributed the remaining 50%. The research grant agreement between Pangu BioPharma, HKUST and the Government of the Hong Kong Special Administration Region became effective April 1, 2020
Expenses					$ 27,000	$ 100,000	$ 100,000	$ 300,000
Development Regulatory And Sales Milestones [Member] | Kyorin Pharmaceutical Co Ltd [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Remaining receivable based on achievement of research milestones				165,000,000
Development Regulatory And Sales Milestones [Member] | Kyorin Pharmaceutical Co Ltd [Member] | Collaboration Revenue [Member]
Research And Development Arrangement Contract To Perform For Others [Line Items]
Upfront payment received					$ 0	$ 0	$ 0	$ 0
Stand-alone selling price of license		$ 100,000		$ 7,900,000

Commitments and Contingencies -

Commitments and Contingencies - Schedule of Future Minimum Payments under Non-cancelable Operating Lease and Reconciliation to Operating Lease Liability (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Leases, Operating [Abstract]
2022	$ 270
2023	1,085
2024	1,675
2025	1,726
2026	1,777
2027 and thereafter	12,933
Less: Amount representing interest	(7,019)
Present value of lease payments	12,447
Less: Current portion of operating lease liability	(657)	$ (980)
Less: Tenant improvement allowance not yet received	(4,572)
Long-term operating lease liability, net of current portion	$ 7,218	$ 398

Commitments and Contingencies_2

Commitments and Contingencies - Additional Information (Detail)	1 Months Ended		3 Months Ended		9 Months Ended
	May 31, 2022 USD ($) ft²	Jul. 31, 2018 ft²	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)
Debt Instrument [Line Items]
Operating lease, cost			$ 300,000	$ 200,000	$ 800,000	$ 700,000
Operating lease, weighted-average remaining lease term			10 years 4 months 24 days		10 years 4 months 24 days
Operating lease, weighted-average discount rate			8.80%		8.80%
Area of office and laboratory space | ft²	23,696
Lease extended maturity Term		2023-05
Lease, option to extend		false
Operating lease, lease not yet commenced, term of contract	124 months
Operating lease, lease not yet commenced, option to extend					We also have one option to extend the Lease Term for five years.
Operating lease, lease not yet commenced, existence of option to extend	true
Operating lease, lease not yet commenced, extension term	5 years
Base rent per square foot	$ 5.75
Annual upward adjustments on base rate, percentage	3%
Allowance for tenant improvements	$ 5,500,000
Additional allowance for tenant improvements	$ 600,000
Base rent amortized percentage	(8.00%)
Security deposit			$ 700,000		$ 700,000
Financing lease, term of contract			48 months		48 months
Financing lease, weighted-average remaining lease term			3 years 9 months 18 days		3 years 9 months 18 days
Financing lease, weighted-average discount rate			7.20%		7.20%
Minimum [Member]
Debt Instrument [Line Items]
Lease space | ft²		24,494
Maximum [Member]
Debt Instrument [Line Items]
Lease space | ft²		20,508
Restricted Cash [Member] | Leased Equipment [Member]
Debt Instrument [Line Items]
Security deposit			$ 1,500,000		$ 1,500,000

Commitments and Contingencies_3

Commitments and Contingencies - Schedule of Future Minimum Payments under Non-cancelable Financing Lease and Reconciliation to Financing Lease Liability (Detail) $ in Thousands	Sep. 30, 2022 USD ($)
Finance Lease, Liability [Abstract]
2022	$ 52
2023	208
2024	208
2025	208
2026	223
Less: Amount representing interest	(123)
Present value of lease payments	776
Less: Current portion of financing lease liability	(158)
Long-term financing lease liability, net of current portion	$ 618

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Detail) - USD ($)	1 Months Ended		9 Months Ended		12 Months Ended
	Mar. 31, 2022	Sep. 30, 2020	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021	Apr. 30, 2022	Mar. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Commission Rate Equal To Gross Proceeds1						3%	3%
Number of common stock shares reserved for issuance			4,971,922
Stock options granted			1,573,844
Inducement Pool Non Qualified Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock shares reserved for issuance	300,000
Aspire Capital [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares issued and sold			0	3,000,000
Shares Issued, Price Per Share				$ 5.09
Proceeds from Issuance of Common Stock				$ 15,200,000
Commitment to purchase shares		$ 20,000,000
Long-term purchase commitment, period		30 months
Long-term purchase commitment, description		upon the terms and subject to the conditions and limitations set forth therein, Aspire Capital is committed to purchase up to an aggregate of $20.0 million of shares of our common stock at our request from time to time during the 30 month term of the Purchase Agreement.
Public Offerings [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Proceeds from Issuance of Common Stock				$ 80,600,000
ATM Offering Program [Member] | Jones Trading Institutional Services LLC [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares Issued, Price Per Share			$ 6.07		$ 4.75
Proceeds from Issuance of Common Stock			$ 1,500,000		$ 4,400,000
ATM Offering Program [Member] | Jones Trading Institutional Services LLC [Member] | Sale Agreement [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Agreed upon value of sale of common stock per transaction							$ 25,000,000
ATM Offering Program [Member] | Jefferies LLC [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares Issued, Price Per Share			$ 3.55
Proceeds from Issuance of Common Stock			$ 3,100,000
ATM Offering Program [Member] | Jefferies LLC [Member] | Sale Agreement [Member] | Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Agreed upon value of sale of common stock per transaction						$ 65,000,000
Common Stock [Member] | Inducement Pool Non Qualified Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options vesting period	4 years
Stock options granted			192,400
Exercise price, granted			$ 4.04
Common Stock [Member] | Inducement Pool Non Qualified Option [Member] | One Year Anniversary [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options vesting period	1 year
Option vesting percentage	25%
Common Stock [Member] | Inducement Pool Non Qualified Option [Member] | Share-based Payment Arrangement, Tranche Two [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options vesting period	3 years
Option vesting percentage	75%
Common Stock [Member] | Maximum [Member] | Inducement Pool Non Qualified Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Options vesting period	10 years
Common Stock [Member] | Public Offerings [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares issued and sold				10,781,250
Shares Issued, Price Per Share				$ 8
Common Stock [Member] | ATM Offering Program [Member] | Jones Trading Institutional Services LLC [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares issued and sold			260,455		986,267
Common Stock [Member] | ATM Offering Program [Member] | Jefferies LLC [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares issued and sold			951,175

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Common Stock Reserved for Future Issuance (Detail)	Sep. 30, 2022 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock shares reserved for issuance	4,971,922
Common Stock Warrants [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock shares reserved for issuance	13,760
Common Stock Options and Restricted Stock Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock shares reserved for issuance	3,082,068
Shares Available Under the 2015 Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock shares reserved for issuance	948,519
Shares Available Under the 2022 Inducement Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock shares reserved for issuance	107,600
Shares Available Under the Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock shares reserved for issuance	819,975

Stockholders' Equity - Summar_2

Stockholders' Equity - Summary of Stock Option Activity (Detail)	9 Months Ended
	Sep. 30, 2022 $ / shares shares
Share-Based Payment Arrangement [Abstract]
Number of Outstanding Stock Options, Beginning Balance | shares	1,412,550
Stock options granted | shares	1,573,844
Number of Outstanding Stock Options, Exercised | shares | shares	(259)
Number of Outstanding Stock Options, Canceled/forfeited/expired | shares	(25,505)
Number of Outstanding Stock Options, Ending Balance | shares	2,960,630
Weighted Average Exercise Price, Beginning Balance | $ / shares	$ 12.01
Weighted Average Exercise Price, Granted | $ / shares	3.44
Weighted Average Exercise Price, Exercised | $ / shares | $ / shares	3.77
Weighted Average Exercise Price, Canceled/forfeited/expired | $ / shares	12.27
Weighted Average Exercise Price, Ending Balance | $ / shares	$ 7.45

Stockholders' Equity - Summar_3

Stockholders' Equity - Summary of Assumptions Used to Determine Fair Value of Employee Stock Option Grants, Employee Stock Purchase Plan and Performance Options with Market Condition (Detail) - Employee Stock Option [Member]	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate, minimum	2.70%	0.80%	1.70%	0.60%
Risk-free interest rate, maximum	2.90%	1.10%	3%	1.10%
Expected volatility, minimum	84.50%	86.30%	84.50%	86.30%
Expected volatility, maximum	84.60%	86.90%	86.50%	104.80%
Expected dividend yield	0%	0%	0%	0%
Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	5 years 11 months 23 days	5 years 11 months 23 days	5 years 11 months 23 days	5 years 6 months
Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (in years)	6 years 21 days	6 years 21 days	6 years 29 days	6 years 29 days

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Restricted Stock Unit Activity (Detail) - Restricted Stock Units [Member]	9 Months Ended
	Sep. 30, 2022 $ / shares shares
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Number of Outstanding Restricted Stock Units, Beginning Balance | shares	7,500
Number of Outstanding Restricted Stock Units, Granted | shares	116,438
Number of Outstanding Restricted Stock Units, Released | shares	(2,500)
Number of Outstanding Restricted Stock Units, Ending Balance | shares	121,438
Weighted Average Grant Date Fair Value, Beginning Balance | $ / shares	$ 4.08
Weighted Average Grant Date Fair Value, Granted | $ / shares	5.13
Weighted Average Grant Date Fair Value, Released | $ / shares	4.13
Weighted Average Grant Date Fair Value, Ending Balance | $ / shares	$ 5.09

Stockholders' Equity - Schedu_2

Stockholders' Equity - Schedule of Allocation of Stock-Based Compensation for All Options and Restricted Stock Units and Stock Issued Pursuant to Our Employee Stock Purchase Plan (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 615	$ 442	$ 1,549	$ 1,200
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	150	70	388	198
General and Administrative Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 465	$ 372	$ 1,161	$ 1,002