Protagonist Therapeutics (PTGX) 10-Q 4 May 23 2023 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2023	Apr. 28, 2023
Document And Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Mar. 31, 2023
Entity File Number	001-37852
Entity Registrant Name	PROTAGONIST THERAPEUTICS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	98-0505495
Entity Address, Address Line One	7707 Gateway Boulevard, Suite 140
Entity Address, City or Town	Newark
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94560-1160
City Area Code	510
Local Phone Number	474-0170
Title of 12(b) Security	Common Stock
Trading Symbol	PTGX
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		57,251,254
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q1
Entity Central Index Key	0001377121
Amendment Flag	false

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Current assets:
Cash and cash equivalents	$ 127,686	$ 125,744
Marketable securities	103,073	111,611
Receivable from collaboration partner	51	10
Prepaid expenses and other current assets	4,926	5,712
Total current assets	235,736	243,077
Property and equipment, net	1,341	1,565
Restricted cash - noncurrent	225	225
Operating lease right-of-use asset	2,556	3,061
Total assets	239,858	247,928
Current liabilities:
Accounts payable	4,021	3,640
Payable to collaboration partner	22	69
Accrued expenses and other payables	16,587	24,955
Operating lease liability - current	2,599	2,515
Total current liabilities	23,229	31,179
Operating lease liability - noncurrent	462	1,141
Total liabilities	23,691	32,320
Commitments and contingencies
Stockholders' equity:
Preferred stock, $0.00001 par value, 10,000,000 shares authorized; no shares issued and outstanding
Common stock, $0.00001 par value, 90,000,000 shares authorized; 51,440,503 and 49,339,252 shares issued and outstanding as of March 31, 2023 and December 31, 2022, respectively	1
Additional paid-in capital	786,768	752,722
Accumulated other comprehensive loss	(122)	(359)
Accumulated deficit	(570,480)	(536,755)
Total stockholders' equity	216,167	215,608
Total liabilities and stockholders' equity	$ 239,858	$ 247,928

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2023	Dec. 31, 2022
Condensed Consolidated Balance Sheets
Preferred stock, par value	$ 0.00001	$ 0.00001
Preferred stock, shares authorized	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.00001	$ 0.00001
Common stock, shares authorized	90,000,000	90,000,000
Common stock, shares issued	51,440,503	49,339,252
Common stock, shares outstanding	51,440,503	49,339,252

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Condensed Consolidated Statements of Operations
License and collaboration revenue		$ 25,722
Revenue from Contract with Customer, Product and Service [Extensible List]	License and Collaboration Agreement	License and Collaboration Agreement
Operating expenses:
Research and development	$ 27,416	$ 36,318
General and administrative	8,605	10,515
Total operating expenses	36,021	46,833
Loss from operations	(36,021)	(21,111)
Interest income	2,491	168
Other (expense) income, net	(195)	13
Net loss	$ (33,725)	$ (20,930)
Net loss per share, basic	$ (0.67)	$ (0.43)
Net loss per share, diluted	$ (0.67)	$ (0.43)
Weighted-average shares used to compute net loss per share, basic	50,573,650	48,752,548
Weighted-average shares used to compute net loss per share, diluted	50,573,650	48,752,548

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Condensed Consolidated Statements of Comprehensive Loss
Net loss	$ (33,725)	$ (20,930)
Other comprehensive loss:
Gain on translation of foreign operations	194	95
Unrealized gain (loss) on marketable securities	43	(268)
Comprehensive loss	$ (33,488)	$ (21,103)

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholder's Equity - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Other Comprehensive (Loss) Gain	Accumulated Deficit	Total
Balance, Beginning at Dec. 31, 2021		$ 709,682	$ (299)	$ (409,362)	$ 300,021
Balance, Beginning (in shares) at Dec. 31, 2021	47,838,330
Increase (Decrease) in Stockholders' Equity
Issuance of common stock, net of issuance costs		14,553			14,553
Issuance of common stock, net of issuance costs (in shares)	422,367
Issuance of common stock under equity incentive and employee stock purchase plans		2,558			2,558
Issuance of common stock under equity incentive and employee stock purchase plans (in shares)	299,131
Shares withheld for net settlement of tax withholding upon vesting of restricted stock units		(186)			(186)
Shares withheld for net settlement of tax withholding upon vesting of restricted stock units (in shares)	(7,726)
Stock-based compensation expense		5,935			5,935
Other comprehensive gain (loss)			(173)		(173)
Net loss				(20,930)	(20,930)
Balance, Ending at Mar. 31, 2022		732,542	(472)	(430,292)	301,778
Balance, Ending (in shares) at Mar. 31, 2022	48,552,102
Balance, Beginning at Dec. 31, 2022		752,722	(359)	(536,755)	$ 215,608
Balance, Beginning (in shares) at Dec. 31, 2022	49,339,252				49,339,252
Increase (Decrease) in Stockholders' Equity
Issuance of common stock, net of issuance costs	$ 1	24,301			$ 24,302
Issuance of common stock, net of issuance costs (in shares)	1,749,199
Issuance of common stock under equity incentive and employee stock purchase plans		2,261			2,261
Issuance of common stock under equity incentive and employee stock purchase plans (in shares)	358,211
Shares withheld for net settlement of tax withholding upon vesting of restricted stock units		(100)			(100)
Shares withheld for net settlement of tax withholding upon vesting of restricted stock units (in shares)	(6,159)
Stock-based compensation expense		7,584			7,584
Other comprehensive gain (loss)			237		237
Net loss				(33,725)	(33,725)
Balance, Ending at Mar. 31, 2023	$ 1	$ 786,768	$ (122)	$ (570,480)	$ 216,167
Balance, Ending (in shares) at Mar. 31, 2023	51,440,503				51,440,503

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash Flows from Operating Activities
Net loss	$ (33,725)	$ (20,930)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation	7,584	5,935
Operating lease right-of-use asset amortization	584	584
(Accretion)/amortization of discount/premium on marketable securities	(1,255)	358
Depreciation	248	249
Other	194
Changes in operating assets and liabilities:
Receivable from collaboration partner	(41)	(23,584)
Prepaid expenses and other assets	787	1,279
Accounts payable	381	5,559
Payable to collaboration partner	(47)	(519)
Accrued expenses and other payables	(8,383)	(5,110)
Deferred revenue		(833)
Operating lease liability	(674)	(654)
Net cash used in operating activities	(34,347)	(37,666)
Cash Flows from Investing Activities
Purchase of marketable securities	(28,060)	(55,832)
Proceeds from maturities of marketable securities	37,896	51,629
Purchases of property and equipment	(10)	(273)
Net cash provided by (used in) investing activities	9,826	(4,476)
Cash Flows from Financing Activities
Proceeds from at-the-market offering, net of issuance costs	24,302	14,553
Proceeds from issuance of common stock upon exercise of stock options and purchases under employee stock purchase plan	2,261	2,558
Tax withholding payments related to net settlement of restricted stock units	(100)	(186)
Net cash provided by financing activities	26,463	16,925
Effect of exchange rate changes on cash, cash equivalents and restricted cash		29
Net increase (decrease) in cash, cash equivalents and restricted cash	1,942	(25,188)
Cash, cash equivalents and restricted cash, beginning of period	125,969	123,890
Cash, cash equivalents and restricted cash, end of period	127,911	98,702
Supplemental Disclosure of Cash Flow Information:
Purchases of property and equipment in accounts payable and accrued liabilities	$ 15	235
Issuance costs related to common stock offering included in accrued liabilities and other payables		$ 25

Organization and Description of

Organization and Description of Business	3 Months Ended
	Mar. 31, 2023
Organization and Description of Business
Organization and Description of Business	PROTAGONIST THERAPEUTICS, INC. Notes to Unaudited Condensed Consolidated Financial Statements Note 1. Protagonist Therapeutics, Inc. (the “Company”) is headquartered in Newark, California. The Company is a biopharmaceutical company with peptide-based new chemical entities rusfertide and JNJ-2113 (formerly known as PN-235) in different stages of clinical development, all derived from the Company’s proprietary technology platform. The Company’s Operating segments are components of an enterprise for which separate financial information is available and is evaluated regularly by the Chief Executive Officer, the Company’s chief operating decision maker, in deciding how to allocate resources and assessing performance. Liquidity As of March 31, 2023, the Company had cash, cash equivalents and marketable securities of $230.8 million. The Company has incurred net losses from operations since inception and had an accumulated deficit of $570.5 million as of March 31, 2023. The Company’s ultimate success depends upon the outcome of its research and development and collaboration activities. The Company expects to incur additional losses in the future and anticipates the need to raise additional capital to continue to execute its long-range business plan. Since the Company’s initial public offering in August 2016, it has financed its operations primarily through proceeds from offerings of common stock and payments received under license and collaboration agreements. Risks and Uncertainties The Company is subject to risks and uncertainties as a result of the prolonged nature of the COVID-19 pandemic and emergent variants with increased transmissibility, even in those who are fully vaccinated. The future impact on the Company’s activities will depend on a number of factors, including, but not limited to, the scope and magnitude of any resurgences in the outbreak and the spread of COVID-19 variants, the timing, extent, effectiveness and durability of COVID-19 vaccine programs or other treatments; and new travel and other restrictions and public health measures. The Company has experienced delays in its existing and planned clinical trials due to worldwide impacts related to the pandemic. The Company’s future results of operations and liquidity could be adversely impacted by further delays in existing and planned clinical trials, continued difficulty in recruiting patients for these clinical trials, delays in manufacturing and collaboration activities, supply chain disruptions, and the ongoing impact on its operating activities and employees. In addition, a recession or market correction related to or amplified by COVID-19 could materially affect the Company’s business. The Company is currently operating in a period of economic uncertainty and capital markets disruption, which has been impacted by domestic and global monetary and fiscal policy, geopolitical instability, including the ongoing military conflict between Russia and Ukraine and the rising tensions between China and Taiwan, a recessionary environment, historically high domestic and global inflation and recent failures of banking and other financial institutions. In particular, the conflict in Ukraine has exacerbated market disruptions, including significant volatility in commodity prices, as well as supply chain interruptions, and has contributed to record inflation globally. The U.S. Federal Reserve and other central banks may be unable to contain inflation through more restrictive monetary policy and inflation may increase or continue for a prolonged period of time. Inflationary factors, such as increases in the cost of clinical supplies, interest rates, overhead costs and transportation costs may adversely affect the Company’s operating results. In addition, the failure of Silicon Valley Bank and other regional banks in the United States between March and May of 2023 has given rise to uncertainty in the security of amounts in deposit accounts uninsured by the Federal Deposit Insurance Corporation. The Company continues to monitor these events and the potential impact on its business. Although the Company does not believe that inflation has had a material impact on its financial position or results of operations to date, it may be adversely affected in the future due to global monetary and fiscal policy, macroeconomic factors, supply chain constraints, consequences associated with COVID-19 and the ongoing conflict between Russia and Ukraine and other factors, and such factors may lead to increases in the cost of manufacturing for and initiation of studies in the Company’s product candidates.

Summary of Significant Accounti

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2023
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	Note 2. Basis of Presentation and Consolidation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) and applicable rules and regulations of the SEC regarding interim financial reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by GAAP have been condensed or omitted, and accordingly the condensed consolidated balance sheet as of March 31, 2023 has been derived from the Company’s unaudited consolidated financial statements at that date but does not include all of the information required by GAAP for complete consolidated financial statements. These unaudited interim condensed consolidated financial statements have been prepared on the same basis as the Company’s annual consolidated financial statements and, in the opinion of management, reflect all adjustments (consisting of normal recurring adjustments) that are necessary for a fair presentation of the Company’s condensed consolidated financial statements. The results of operations for the three months ended March 31, 2023 are not necessarily indicative of the results to be expected for the year ending December 31, 2023 or for any future period. Effective January 1, 2023, the financial statements of Protagonist Australia use the U.S. dollar as the functional currency, which reflects the expected nature of the ongoing operations of this subsidiary. The cumulative translation adjustment as of January 1, 2023 related to this subsidiary was not material. Prior to January 1, 2023, the financial statements of Protagonist Australia used the Australian dollar as the functional currency since the majority of expense transactions occurred in such currency. Foreign currency translation gains and losses are reported as a component of stockholders’ equity in accumulated other comprehensive loss on the condensed consolidated balance sheets. The accompanying unaudited condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto for the year ended December 31, 2022 included in the Company’s Annual Report on Form 10-K, filed with the SEC on March 15, 2023. Principles of Consolidation The accompanying unaudited interim condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiary. All intercompany transactions and balances have been eliminated upon consolidation. Use of Estimates The preparation of the condensed consolidated financial statements in conformity with GAAP requires management to make estimates, assumptions and judgments that affect the reported amounts of assets and liabilities and disclosure of contingent liabilities as of the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, management evaluates its estimates, including those related to revenue recognition, accruals for research and development activities, stock-based compensation, income taxes, marketable securities and leases. Estimates related to revenue recognition include actual costs incurred versus total estimated costs of the Company’s deliverables to determine percentage of completion in addition to the application and estimates of potential revenue constraints in the determination of the transaction price under its license and collaboration agreements. Management bases these estimates on historical and anticipated results, trends, and various other assumptions that the Company believes are reasonable under the circumstances, including assumptions as to forecasted amounts and future events. Actual results could differ materially from these estimates. Due to the prolonged nature of the COVID-19 pandemic, military conflict between Ukraine and Russia, rising tensions between China and Taiwan and inflationary pressures, there has been uncertainty and disruption in the global economy and financial markets. The Company has taken into consideration any known impacts in its accounting estimates to date and is not aware of any additional specific events or circumstances that would require any additional updates to its estimates or judgments or a revision of the carrying value of its assets or liabilities as of the issuance of this report. These estimates may change as new events occur and additional information is obtained. Actual results could differ materially from these estimates under different assumptions or conditions. Cash as Reported in Condensed Consolidated Statements of Cash Flows Cash as reported in the condensed consolidated statements of cash flows includes the aggregate amounts of cash and cash equivalents and the restricted cash as presented on the condensed consolidated balance sheets. Cash as reported in the condensed consolidated statements of cash flows consists of (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ 2023 2022 Cash and cash equivalents ​ $ 127,686 ​ $ 98,477 Restricted cash - noncurrent ​ 225 ​ 225 Total cash reported on condensed consolidated statements of cash flows ​ $ 127,911 ​ $ 98,702 ​ Investment Impairment ​ As of each reporting date, the Company assesses each of its investments in available-for-sale debt securities whose fair value is below its cost basis to determine if the investment’s impairment is due to credit-related factors or noncredit-related factors. Factors considered in determining whether an impairment is credit-related include the extent to which the investment’s fair value is less than its cost basis, declines in published credit ratings, issuer default on interest or principal payments, and declines in the financial condition and near-term prospects of the issuer. Credit-related impairments on available-for-sale debt securities are recognized as an allowance for credit losses with a corresponding adjustment to other income (expense), net. The portion of the impairment that is not credit-related is recorded as a reduction of other comprehensive income (loss), net of applicable taxes. ​ The Company has elected to exclude accrued interest from both the fair value and the amortized cost basis of the available-for-sale debt securities for the purposes of identifying and measuring an impairment. The Company writes off accrued interest as a reduction of interest income when an issuer has defaulted on interest payments due on a security. ​ ​ Significant Accounting Policies ​ Other than the change in Protagonist Australia functional currency from Australian dollar to U.S. dollar effective January 1, 2023 and the investment impairment policy, as discussed above, there have been no material changes to the Company’s significant accounting policies during the three months ended March 31, 2023 as compared to those disclosed in Note 2. Summary of Significant Accounting Policies included in our Annual Report on Form 10-K for the year ended December 31, 2022. ​ Recently Adopted Accounting Pronouncement In June 2016, the Financial Accounting Standard Board (“FASB”) issued Accounting Standard Update (“ASU”) 2016-13, Financial Instruments - Credit Losses (Topic 326) recognized in the financial statements. The measurement of expected credit losses is based on historical credit loss information as well as current and future economic factors. ASU 2016-13 also eliminates the concept of “other-than-temporary” impairment when evaluating available-for-sale debt securities and instead focuses on determining whether any impairment is a result of credit loss or other factors. In November 2019, the FASB issued ASU 2019-10, Financial Instruments – Credit Losses (Topic 326): Effective Dates

License and Collaboration Agree

License and Collaboration Agreement	3 Months Ended
	Mar. 31, 2023
License and Collaboration Agreement..
License and Collaboration Agreement
License and Collaboration Agreement	Note 3. License and Collaboration Agreement Agreement Terms On July 27, 2021, the Company entered into an Amended and Restated License and Collaboration Agreement (the “Restated Agreement”) with Janssen Biotech, Inc., a Pennsylvania corporation (“Janssen”), which amended and restated the License and Collaboration Agreement, effective July 13, 2017, by and between the Company and Janssen (the “Original Agreement’), as amended by the first amendment, effective May 7, 2019 (the “First Amendment”). Prior to January 1, 2023, Janssen was a related party to the Company as Johnson & Johnson Innovation - JJDC, Inc. was a significant (greater than 5%) stockholder of the Company, and both companies are subsidiaries of Johnson & Johnson. Upon the effectiveness of the Original Agreement, the Company received a non-refundable, upfront cash payment of $50.0 million from Janssen. Upon the effectiveness of the First Amendment, the Company received a $25.0 million payment from Janssen in 2019. The Company received a $5.0 million payment triggered by the successful nomination of a second-generation oral Interleukin (“IL”)-23 receptor antagonist development compound (“second-generation compound”) during the first quarter of 2020 and received a $7.5 million payment triggered by the completion of data collection activities for the first Phase 1 clinical trial of a second-generation compound during the fourth quarter of 2021. The Company received a $25.0 million milestone payment in connection with the dosing of the third patient in the first Phase 2 clinical trial for a second-generation compound during the second quarter of 2022. The Restated Agreement relates to the development, manufacture and commercialization of oral IL-23 receptor antagonist drug candidates. The candidates nominated for initial development pursuant to the Restated Agreement included PTG-200 (JNJ-67864238), PN-232 (JNJ-75105186) and JNJ-2113 (JNJ-77242113) (formerly known as PN-235). PTG-200 is an oral IL-23 receptor antagonist that was in Phase 2a development for the treatment of Crohn’s disease (“CD”). During the fourth quarter of 2021, following a pre-specified interim analysis criteria, a portfolio decision was made by Janssen to stop further development of both PTG-200 and PN-232 in favor of advancing JNJ-2113, based on its superior potency and overall pharmacokinetic and pharmacodynamic profile. Janssen is primarily responsible for the conduct of all future trials, including these anticipated Phase 2 trials, and the Company is primarily responsible for the conduct of the second-generation Phase 1 trials. ​ The Restated Agreement enables Janssen to develop collaboration compounds for multiple indications. Under the Restated Agreement, Janssen is required to use commercially reasonable efforts to develop at least one collaboration compound for at least two indications. Upcoming potential development milestones for second-generation compounds include: ● $10.0 million upon the dosing of the third patient in the first Phase 2 clinical trial for any second-generation compound for a second indication (i.e., an indication different than the indication which triggered the $25.0 million milestone received during the second quarter of 2022 described above); ● $50.0 million upon the dosing of the third patient in a Phase 3 clinical trial for a second-generation compound for any indication; ● $15.0 million upon the dosing of the third patient in a Phase 3 clinical trial for a second-generation compound for a second indication; and ● $115.0 million upon a Phase 3 clinical trial for a second-generation compound for any indication meeting its primary clinical endpoint. Pursuant to the Restated Agreement, the Company remains eligible to receive tiered royalties on net product sales at percentages ranging from mid-single digits to ten percent. The sales milestone payments in the Original Agreement also remain the same in the Restated Agreement. Pursuant to both the Original and Restated Agreements, payments to the Company for research and development services are generally billed and collected as services are performed or assets are delivered, including research activities and Phase 1 and Phase 2 development activities. Janssen bills the Company for its share of the PTG-200 Phase 2a development costs as expenses are incurred by Janssen. Milestone payments are received after the related milestones are achieved. Janssen retains exclusive, worldwide rights to develop and commercialize IL-23 receptor antagonist compounds derived from the research collaboration conducted under the Original Agreement, or Janssen’s further research under the Restated Agreement. Any further research and development will be conducted by Janssen. The Company will have the right to co-detail (for CD and ulcerative colitis indications) up to two of the IL-23 receptor antagonist compounds under the collaboration in the U.S. market. The Restated Agreement remains in effect until the royalty obligations cease following patent and regulatory expiry, unless terminated earlier. Upon a termination of the Restated Agreement, all rights revert back to the Company, and in certain circumstances, if such termination occurs during ongoing clinical trials, Janssen would, if requested, provide certain financial and operational support to the Company for the completion of such trials. Revenue Recognition The Restated Agreement contains a single performance obligation for the development license; Phase 1 development services for PTG-200, PN-232 and JNJ-2113 (formerly known as PN-235); the Company’s services associated with Phase 2a development for PTG-200 in CD; the initial year of second-generation compound research services; and all other such services that the Company may perform at the request of Janssen to support the development of PTG-200 through Phase 2a and PN-232 and JNJ-2113 through Phase 1. Under the Restated Agreement, development services performed by the Company for PTG-200 beyond Phase 2a and PN-232 and JNJ-2113 beyond Phase 1 are no longer required. The contract duration is defined as the period in which parties to the contract have present enforceable rights and obligations. For revenue recognition purposes, the duration of the Restated Agreement for the identified single initial performance obligations began on the Original Agreement effective date of July 13, 2017 and ended upon the completion of Phase 1 clinical trials for PN-232 and JNJ-2113. Final activities related to these trials were completed as of June 30, 2022. The transaction price of the initial performance obligation under the Restated Agreement was $131.7 million as of June 30, 2022, and increase of $0.2 million from the transaction price of $131.5 million as of March 31, 2022. In order to determine the transaction price, the Company evaluated all payments to be received during the duration of the contract, net of development costs reimbursement expected to be payable to Janssen. The transaction price as of June 30, 2022 included $112.5 million of nonrefundable payments received to date, $17.9 million of reimbursement from Janssen for services performed for IL-23 receptor antagonist compound research costs and other services, and variable consideration consisting of $8.2 million of development cost reimbursement from Janssen, partially offset by $6.9 million of net cost reimbursement due to Janssen for services performed. The Company concluded that the variable consideration constraint was appropriately reflected in the estimated transaction price as of June 30, 2022, and that the achievement of future milestones was subject to additional development and/or regulatory uncertainty and therefore it was not probable at June 30, 2022 that a material reversal of such revenues would not occur. Janssen also opted in for certain additional services to be performed by the Company that were outside the initial performance obligation. Revenue for these additional services was recognized as these services were performed. No license and collaboration revenue was recognized for the three months ended March 31, 2023 because the Company completed its performance obligation under the collaboration as of June 30, 2022. For the three months ended March 31, 2022, the Company recognized license and collaboration revenue of $25.7 million. License and collaboration revenue for the three months ended March 31, 2022 was primarily related to the transaction price under the Restated Agreement recognized based on proportional performance. The following tables present changes in the Company’s contract assets and liabilities during the periods presented (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at ​ ​ ​ ​ ​ Balance at ​ ​ Beginning of ​ ​ ​ ​ ​ End of Three Months Ended March 31, 2023 Period ​ Additions Deductions Period Contract assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Receivable from collaboration partner ​ $ 10 ​ $ 41 ​ ​ — ​ $ 51 Contract liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Payable to collaboration partner ​ $ 69 ​ $ 11 ​ ​ (58) ​ $ 22 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at ​ ​ ​ ​ ​ ​ ​ Balance at ​ ​ Beginning of ​ ​ ​ ​ ​ End of Three Months Ended March 31, 2022 Period ​ Additions Deductions Period Contract assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Receivable from collaboration partner ​ $ 1,566 ​ $ 25,150 ​ $ (1,566) ​ $ 25,150 Contract liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Deferred revenue ​ $ 1,601 ​ $ 25,658 ​ $ (26,491) ​ $ 768 Payable to collaboration partner ​ $ 899 ​ $ 330 ​ $ (849) ​ $ 380 ​ During the three months ended March 31, 2023 and 2022, the Company recognized revenue of zero and $13,000, respectively, from amounts included in the deferred revenue contract liability balance at the beginning of each period. None of the costs to obtain or fulfill the contract were capitalized.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2023
Fair Value Measurements
Fair Value Measurements	Note 4. Fair Value Measurements Financial assets and liabilities are recorded at fair value. The accounting guidance for fair value provides a framework for measuring fair value, clarifies the definition of fair value and expands disclosures regarding fair value measurements. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the reporting date. The accounting guidance establishes a three-tiered hierarchy, which prioritizes the inputs used in the valuation methodologies in measuring fair value as follows: Level 1 Level 2— Level 3 In determining fair value, the Company utilizes quoted market prices, broker or dealer quotations, or valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible and considers counterparty credit risk in its assessment of fair value. The following tables present the fair value of the Company’s financial assets determined using the inputs defined above (in thousands). ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2023 ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 46,007 ​ $ — ​ $ — $ 46,007 Commercial paper ​ — ​ ​ 87,299 ​ — 87,299 Corporate debt securities ​ ​ — ​ ​ 10,870 ​ ​ — ​ ​ 10,870 U.S. Treasury and agency securities ​ ​ — ​ ​ 79,783 ​ ​ — ​ ​ 79,783 Total financial assets ​ $ 46,007 ​ $ 177,952 $ — $ 223,959 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 54,292 ​ $ — ​ $ — $ 54,292 Commercial paper ​ — ​ 110,227 ​ — 110,227 Corporate debt securities ​ — ​ 10,741 — 10,741 U.S. Treasury and agency securities ​ ​ ​ ​ ​ 57,242 ​ ​ — 57,242 Total financial assets ​ $ 54,292 ​ $ 178,210 $ — $ 232,502 ​ The Company’s commercial paper, corporate debt securities, U.S. Treasury and agency securities, including U.S. Treasury bills, are classified as Level 2 as they were valued based upon quoted market prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active and model-based valuation techniques, for which all significant inputs are observable in the market or can be corroborated by observable market data for substantially the full term of the assets. The carrying amount of the Company’s remaining financial assets and liabilities, including cash, receivables and payables, approximates their fair value due to their short-term nature.

Cash Equivalents and Marketable

Cash Equivalents and Marketable Securities	3 Months Ended
	Mar. 31, 2023
Cash Equivalents and Marketable Securities
Cash Equivalents and Marketable Securities	Note 5. Cash Equivalents and Marketable Securities ​ Cash equivalents and marketable securities consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2023 ​ ​ Amortized ​ Gross Unrealized ​ ​ Cost Gains Losses Fair Value Money market funds ​ $ 46,007 ​ $ — ​ $ — ​ $ 46,007 Commercial paper ​ 87,316 ​ ​ — ​ ​ (17) ​ 87,299 Corporate debt securities ​ ​ 10,877 ​ ​ 5 ​ ​ (12) ​ ​ 10,870 U.S. Treasury and agency securities ​ ​ 79,770 ​ ​ 70 ​ ​ (57) ​ ​ 79,783 Total cash equivalents and marketable securities ​ $ 223,970 ​ $ 75 $ (86) ​ $ 223,959 Classified as: ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash equivalents ​ ​ ​ ​ ​ ​ ​ $ 120,886 Marketable securities ​ ​ ​ ​ ​ ​ ​ 103,073 Total cash equivalents and marketable securities ​ ​ ​ ​ ​ ​ ​ $ 223,959 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ ​ Amortized ​ Gross Unrealized ​ ​ Cost Gains Losses Fair Value Money market funds ​ $ 54,292 ​ $ — $ — ​ $ 54,292 Commercial paper ​ 110,257 ​ — (30) ​ 110,227 Corporate debt securities ​ 10,756 ​ — (15) ​ 10,741 U.S. Treasury and agency securities ​ ​ 57,251 ​ ​ 27 ​ ​ (36) ​ ​ 57,242 Total cash equivalents and marketable securities ​ $ 232,556 ​ $ 27 $ (81) ​ $ 232,502 Classified as: ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash equivalents ​ ​ ​ ​ ​ ​ ​ $ 120,891 Marketable securities ​ ​ ​ ​ ​ ​ ​ 111,611 Total cash equivalents and marketable securities ​ ​ ​ ​ ​ ​ ​ $ 232,502 ​ Marketable securities of $103.1 million and $111.6 million held at March 31, 2023 and December 31, 2022, respectively, had contractual maturities of less than one year. The Company does not intend to sell its securities that are in an unrealized loss position, and it is not more likely than not that the Company will be required to sell its securities before recovery of their amortized cost basis, which may be at maturity. There were no realized gains or realized losses on marketable securities for the periods presented. The Company evaluated securities with unrealized losses to determine whether such losses, if any, are due to credit-related factors and determined that there were no credit-related losses to be recognized as of March 31, 2023.

Balance Sheet Components

Balance Sheet Components	3 Months Ended
	Mar. 31, 2023
Balance Sheet Components
Balance Sheet Components	Note 6. Prepaid Expenses and Other Current Assets Prepaid expenses and other current assets consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ ​ 2023 ​ 2022 Prepaid clinical and research related expenses ​ $ 1,492 ​ $ 2,746 Prepaid insurance ​ ​ 1,401 ​ ​ 1,417 Prepaid license ​ ​ 542 ​ ​ 489 Other prepaid expenses ​ 1,491 ​ 1,018 Other receivable ​ ​ — ​ ​ 42 Prepaid expenses and other current assets ​ $ 4,926 ​ $ 5,712 ​ Property and Equipment, Net Property and equipment, net consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ ​ 2023 ​ 2022 Laboratory equipment ​ $ 4,831 ​ $ 4,817 Furniture and computer equipment ​ 1,089 ​ 1,089 Leasehold improvements ​ 913 ​ 913 Total property and equipment ​ 6,833 ​ 6,819 Accumulated depreciation ​ (5,492) ​ (5,254) Property and equipment, net ​ $ 1,341 ​ $ 1,565 ​ ​ Accrued Expenses and Other Payables Accrued expenses and other payables consisted of the following (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ 2023 ​ 2022 Accrued clinical and research related expenses ​ $ 13,108 ​ $ 19,109 Accrued employee related expenses ​ 2,080 ​ 4,967 Accrued professional service fees ​ ​ 1,065 ​ ​ 464 Other ​ 334 ​ 415 Total accrued expenses and other payables ​ $ 16,587 ​ $ 24,955 ​

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2023
Stockholders' Equity
Stockholders' Equity	Note 7. Stockholders’ Equity In August 2022, the Company entered into an Open Market Sale Agreement SM (the “Sales Agreement”), pursuant to which the Company could offer and sell up to $100.0 million of shares of common stock from time to time in the “at-the-market” offerings (the “2022 ATM Facility”). As of and for the three months ended March 31, 2023, the Company sold 1,749,199 shares of its common stock under the 2022 ATM Facility for net proceeds of $24.3 million, after deducting issuance costs. ​ In November 2019, the Company entered into an Open Market Sale Agreement SM (the “Prior Sales Agreement”), pursuant to which the Company could offer and sell up to $75.0 million of shares of common stock from time to time in the “at-the-market” offerings (the “2019 ATM Facility”). During the year ended December 31, 2022, the Company sold 422,367 shares of its common stock under the 2019 ATM Facility for net proceeds of $14.6 million, after deducting issuance costs. The Prior Sales Agreement was terminated in connection with and replaced by the Sales Agreement in August 2022. In August 2018, the Company entered into a Securities Purchase Agreement with certain accredited investors (each, an “Investor” and, collectively, the “Investors”), pursuant to which the Company sold an aggregate of 2,750,000 shares of its common stock at a price of $8.00 per share, for aggregate net proceeds of $21.7 million, after deducting offering expenses payable by the Company. In a concurrent private placement, the Company issued the Investors warrants to purchase an aggregate of 2,750,000 shares of its common stock (each, a “Warrant” and, collectively, the “Warrants”). Each Warrant is exercisable from August 8, 2018 through August 8, 2023. Warrants to purchase 1,375,000 shares of the Company’s common stock have an exercise price of $10.00 per share and Warrants to purchase 1,375,000 shares of the Company’s common stock have an exercise price of $15.00 per share. The exercise price and number of shares of common stock issuable upon the exercise of the Warrants (the “Warrant Shares”) are subject to adjustment in the event of any stock dividends and splits, reverse stock split, recapitalization, reorganization or similar transaction, as described in the Warrants. Under certain circumstances, the Warrants may be exercisable on a “cashless” basis. In connection with the issuance and sale of the common stock and Warrants, the Company granted the Investors certain registration rights with respect to the Warrants and the Warrant Shares. The common stock and warrants are classified as equity in accordance with Accounting Standards Codification Topic 480 , Distinguishing Liabilities from Equity (“ASC 480”)

Equity Plans

Equity Plans	3 Months Ended
	Mar. 31, 2023
Equity Plans
Equity Plans	Note 8. Equity Plans Equity Incentive Plan In July 2016, the Company’s board of directors and stockholders approved the Company’s 2016 Equity Incentive Plan (the “2016 Plan”) to replace the 2007 Stock Option Plan. The 2016 Plan is administered by the board of directors, or a committee appointed by the board of directors, which determines the types of awards to be granted, including the number of shares subject to the awards, the exercise price and the vesting schedule. Awards granted under the 2016 Plan expire no later than ten years from the date of grant. As of March 31, 2023, 892,905 shares were available for issuance under the 2016 Plan. Inducement Plan In May 2018, the Company’s board of directors approved the Company’s 2018 Inducement Plan (as subsequently amended, the “2018 Inducement Plan”) is a non-stockholder approved stock plan, under which the Company awards options and restricted stock unit awards to persons that were not previously employees or directors of the Company, or following a bona fide period of non-employment, as an inducement material to such persons entering into employment with the Company, within the meaning of Rule 5635(c)(4) of the Nasdaq Listing Rules. The 2018 Inducement Plan is administered by the board of directors or the Compensation Committee of the board, which determines the types of awards to be granted, including the number of shares subject to the awards, the exercise price and the vesting schedule. Awards granted under the 2018 Inducement Plan expire no later than ten years from the date of grant. As of March 31, 2023, 574,772 shares were available for issuance under the 2018 Inducement Plan. Stock Options Stock option activity under the Company’s equity incentive and inducement plans is set forth below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ Weighted- ​ ​ ​ ​ ​ ​ Average ​ Average ​ ​ ​ ​ ​ ​ Exercise ​ Remaining ​ Aggregate ​ ​ Options ​ Price Per ​ Contractual ​ Intrinsic ​ Outstanding Share Life (years) Value (1) ​ ​ ​ ​ ​ ​ ​ ​ ​ (in millions) Balances at December 31, 2022 6,240,509 $ 19.03 ​ ​ ​ Options granted 2,198,750 ​ ​ 12.17 ​ ​ Options exercised (128,722) ​ ​ 13.49 ​ ​ ​ Options forfeited ​ (148,693) ​ ​ 26.21 ​ ​ ​ ​ ​ Balances at March 31, 2023 8,161,844 $ 17.14 ​ 7.74 ​ $ 63.3 Options exercisable – March 31, 2023 ​ 3,935,198 $ 16.82 ​ 6.23 ​ ​ 30.8 Options vested and expected to vest – March 31, 2023 ​ 8,161,844 ​ $ 17.14 7.74 ​ $ 63.3 (1) The aggregate intrinsic values were calculated as the difference between the exercise price of the options and the closing price of the Company’s common stock on March 31, 2023. The calculation excludes options with an exercise price higher than the closing price of the Company’s common stock on March 31, 2023. The estimated weighted-average grant-date fair value of common stock underlying options granted to employees during the three months ended March 31, 2023 was $10.05 per share. Stock Options Valuation Assumptions The fair value of employee stock option awards was estimated at the date of grant using a Black-Scholes option-pricing model with the following assumptions: ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ 2023 ​ 2022 Expected term (in years) 5.27 - 6.02 5.27 - 6.08 Expected volatility 106.3% - 110.1% ​ 97.1% - 98.2% Risk-free interest rate 3.57% - 3.59% ​ 1.64% - 2.13% Dividend yield — — ​ In determining the fair value of the options granted, the Company uses the Black-Scholes option-pricing model and assumptions discussed below. Each of these inputs is subjective and generally requires judgment to determine. Expected Term Expected Volatility Risk-Free Interest Rate Expected Dividend Restricted Stock Units Restricted stock unit (“RSU”) activity under the Company’s equity incentive plans is set forth below: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ Shares Fair Value Unvested RSUs at December 31, 2022 ​ 637,436 ​ $ 19.29 Granted ​ 396,775 ​ ​ 18.57 Vested ​ (160,884) ​ ​ 15.83 Forfeited ​ (9,215) ​ ​ 20.86 Unvested RSUs at March 31, 2023 ​ 864,112 ​ $ 16.26 ​ Performance Stock Units As of March 31, 2023 and December 31, 2022, 199,500 unvested performance stock units (“PSUs”) were outstanding under the Company’s equity incentive plans, with a weighted average grant date fair value of $14.59 per share. The terms of the unvested PSUs provide for 100% of shares to be earned based on the achievement of certain pre-determined performance objectives, subject to the participant’s continued employment. The PSUs will vest, if at all, upon certification by the compensation committee of the Board of Directors of the actual achievement of the related performance objectives, subject to specified change of control exceptions. ​ Stock-based compensation expense associated with PSUs is based on the fair value of the Company’s common stock on the grant date, which equals the closing price of the Company’s common stock on the grant date. The Company recognizes compensation expense over the vesting period of the awards that are ultimately expected to vest when the achievement of the related performance objectives becomes probable. The total grant date fair value of unvested PSUs outstanding as of March 31, 2023 was $2.9 million. As of March 31, 2023, the achievement of the related performance objectives was deemed not probable and, accordingly, no stock-based compensation for the PSUs has been recognized as expense as of March 31, 2023. Employee Stock Purchase Plan ​ The Company’s 2016 Employee Stock Purchase Plan (“2016 ESPP”) allows eligible employees to purchase shares of the Company’s common stock at a discount through payroll deductions of up to 15% of their eligible compensation. At the end of each offering period, eligible employees are able to purchase shares at 85% of the lower of the fair market value of the Company’s common stock at the beginning of the offering period or at the end of each applicable purchase period. During the three months ended March 31, 2023, a total of 68,605 shares of common stock were issued under the 2016 ESPP, and 1,486,685 shares of common stock remained available for issuance as of March 31, 2023. Stock-Based Compensation ​ Total stock-based compensation expense was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ 2023 2022 Research and development ​ $ 4,582 ​ $ 3,326 General and administrative ​ 3,002 ​ 2,609 Total stock-based compensation expense ​ $ 7,584 ​ $ 5,935 ​ As of March 31, 2023, total unrecognized stock-based compensation expense was approximately $66.8 million, which the Company expects to recognize over a weighted-average period of approximately 2.7 years.

Net Loss per Share

Net Loss per Share	3 Months Ended
	Mar. 31, 2023
Net Loss per Share
Net Loss per Share	Note 9. Net Loss per Share As the Company had net losses for the three months ended March 31, 2023 and 2022, all potential weighted average dilutive common shares were determined to be anti-dilutive. The following table sets forth the computation of basic and diluted net loss per share (in thousands, except share and per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ 2023 2022 Numerator: ​ ​ ​ ​ ​ ​ Net loss ​ $ (33,725) ​ $ (20,930) Denominator: ​ ​ ​ ​ ​ ​ Weighted-average shares used to compute net loss per common share, basic and diluted ​ 50,573,650 ​ 48,752,548 Net loss per share, basic and diluted ​ $ (0.67) ​ $ (0.43) ​ The following outstanding shares of potentially dilutive securities have been excluded from diluted net loss per share computations for the periods presented because their inclusion would be anti-dilutive: ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ 2023 2022 Options to purchase common stock ​ 8,161,844 6,809,610 Common stock warrants ​ 2,750,000 ​ 2,750,000 Restricted stock units ​ 864,112 ​ 606,810 Performance stock units ​ 199,500 ​ 105,500 ESPP shares ​ 24,998 ​ 19,762 Total 12,000,454 10,291,682 ​

Subsequent Event

Subsequent Event	3 Months Ended
	Mar. 31, 2023
Subsequent Event
Subsequent Event	​ ​ Note 10. Subsequent Event ​ In April 2023, the Company completed an underwritten public offering of 5,000,000 shares of its common stock at a public offering price of $20.00 per share and issued an additional 750,000 shares of common stock at a price of $20.00 per share following the underwriters’ exercise of their option to purchase additional shares. Net proceeds, after deducting underwriting commissions and offering costs paid by the Company, were approximately $107.7 million.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2023
Summary of Significant Accounting Policies
Basis of Presentation and Consolidation	Basis of Presentation and Consolidation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“GAAP”) and applicable rules and regulations of the SEC regarding interim financial reporting. As permitted under those rules, certain footnotes or other financial information that are normally required by GAAP have been condensed or omitted, and accordingly the condensed consolidated balance sheet as of March 31, 2023 has been derived from the Company’s unaudited consolidated financial statements at that date but does not include all of the information required by GAAP for complete consolidated financial statements. These unaudited interim condensed consolidated financial statements have been prepared on the same basis as the Company’s annual consolidated financial statements and, in the opinion of management, reflect all adjustments (consisting of normal recurring adjustments) that are necessary for a fair presentation of the Company’s condensed consolidated financial statements. The results of operations for the three months ended March 31, 2023 are not necessarily indicative of the results to be expected for the year ending December 31, 2023 or for any future period. Effective January 1, 2023, the financial statements of Protagonist Australia use the U.S. dollar as the functional currency, which reflects the expected nature of the ongoing operations of this subsidiary. The cumulative translation adjustment as of January 1, 2023 related to this subsidiary was not material. Prior to January 1, 2023, the financial statements of Protagonist Australia used the Australian dollar as the functional currency since the majority of expense transactions occurred in such currency. Foreign currency translation gains and losses are reported as a component of stockholders’ equity in accumulated other comprehensive loss on the condensed consolidated balance sheets. The accompanying unaudited condensed consolidated financial statements and related financial information should be read in conjunction with the audited consolidated financial statements and the related notes thereto for the year ended December 31, 2022 included in the Company’s Annual Report on Form 10-K, filed with the SEC on March 15, 2023.
Principles of Consolidation	Principles of Consolidation The accompanying unaudited interim condensed consolidated financial statements include the accounts of the Company and its wholly owned subsidiary. All intercompany transactions and balances have been eliminated upon consolidation.
Use of Estimates	Use of Estimates The preparation of the condensed consolidated financial statements in conformity with GAAP requires management to make estimates, assumptions and judgments that affect the reported amounts of assets and liabilities and disclosure of contingent liabilities as of the date of the condensed consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. On an ongoing basis, management evaluates its estimates, including those related to revenue recognition, accruals for research and development activities, stock-based compensation, income taxes, marketable securities and leases. Estimates related to revenue recognition include actual costs incurred versus total estimated costs of the Company’s deliverables to determine percentage of completion in addition to the application and estimates of potential revenue constraints in the determination of the transaction price under its license and collaboration agreements. Management bases these estimates on historical and anticipated results, trends, and various other assumptions that the Company believes are reasonable under the circumstances, including assumptions as to forecasted amounts and future events. Actual results could differ materially from these estimates. Due to the prolonged nature of the COVID-19 pandemic, military conflict between Ukraine and Russia, rising tensions between China and Taiwan and inflationary pressures, there has been uncertainty and disruption in the global economy and financial markets. The Company has taken into consideration any known impacts in its accounting estimates to date and is not aware of any additional specific events or circumstances that would require any additional updates to its estimates or judgments or a revision of the carrying value of its assets or liabilities as of the issuance of this report. These estimates may change as new events occur and additional information is obtained. Actual results could differ materially from these estimates under different assumptions or conditions.
Cash as Reported in Consolidated Statements of Cash Flows	Cash as Reported in Condensed Consolidated Statements of Cash Flows Cash as reported in the condensed consolidated statements of cash flows includes the aggregate amounts of cash and cash equivalents and the restricted cash as presented on the condensed consolidated balance sheets.
Investment Impairment	Investment Impairment ​ As of each reporting date, the Company assesses each of its investments in available-for-sale debt securities whose fair value is below its cost basis to determine if the investment’s impairment is due to credit-related factors or noncredit-related factors. Factors considered in determining whether an impairment is credit-related include the extent to which the investment’s fair value is less than its cost basis, declines in published credit ratings, issuer default on interest or principal payments, and declines in the financial condition and near-term prospects of the issuer. Credit-related impairments on available-for-sale debt securities are recognized as an allowance for credit losses with a corresponding adjustment to other income (expense), net. The portion of the impairment that is not credit-related is recorded as a reduction of other comprehensive income (loss), net of applicable taxes. ​ The Company has elected to exclude accrued interest from both the fair value and the amortized cost basis of the available-for-sale debt securities for the purposes of identifying and measuring an impairment. The Company writes off accrued interest as a reduction of interest income when an issuer has defaulted on interest payments due on a security.
Recently Adopted Accounting Pronouncement	Recently Adopted Accounting Pronouncement In June 2016, the Financial Accounting Standard Board (“FASB”) issued Accounting Standard Update (“ASU”) 2016-13, Financial Instruments - Credit Losses (Topic 326) recognized in the financial statements. The measurement of expected credit losses is based on historical credit loss information as well as current and future economic factors. ASU 2016-13 also eliminates the concept of “other-than-temporary” impairment when evaluating available-for-sale debt securities and instead focuses on determining whether any impairment is a result of credit loss or other factors. In November 2019, the FASB issued ASU 2019-10, Financial Instruments – Credit Losses (Topic 326): Effective Dates

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Mar. 31, 2023
Summary of Significant Accounting Policies
Schedule of cash as reported in the consolidated statements of cash flows	​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ 2023 2022 Cash and cash equivalents ​ $ 127,686 ​ $ 98,477 Restricted cash - noncurrent ​ 225 ​ 225 Total cash reported on condensed consolidated statements of cash flows ​ $ 127,911 ​ $ 98,702

License and Collaboration Agr_2

License and Collaboration Agreement (Tables)	3 Months Ended
	Mar. 31, 2023
License and Collaboration Agreement.
Schedule of changes in contract assets and liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at ​ ​ ​ ​ ​ Balance at ​ ​ Beginning of ​ ​ ​ ​ ​ End of Three Months Ended March 31, 2023 Period ​ Additions Deductions Period Contract assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Receivable from collaboration partner ​ $ 10 ​ $ 41 ​ ​ — ​ $ 51 Contract liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Payable to collaboration partner ​ $ 69 ​ $ 11 ​ ​ (58) ​ $ 22 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at ​ ​ ​ ​ ​ ​ ​ Balance at ​ ​ Beginning of ​ ​ ​ ​ ​ End of Three Months Ended March 31, 2022 Period ​ Additions Deductions Period Contract assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Receivable from collaboration partner ​ $ 1,566 ​ $ 25,150 ​ $ (1,566) ​ $ 25,150 Contract liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Deferred revenue ​ $ 1,601 ​ $ 25,658 ​ $ (26,491) ​ $ 768 Payable to collaboration partner ​ $ 899 ​ $ 330 ​ $ (849) ​ $ 380

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2023
Fair Value Measurements
Schedule of fair value of financial assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2023 ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 46,007 ​ $ — ​ $ — $ 46,007 Commercial paper ​ — ​ ​ 87,299 ​ — 87,299 Corporate debt securities ​ ​ — ​ ​ 10,870 ​ ​ — ​ ​ 10,870 U.S. Treasury and agency securities ​ ​ — ​ ​ 79,783 ​ ​ — ​ ​ 79,783 Total financial assets ​ $ 46,007 ​ $ 177,952 $ — $ 223,959 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2022 ​ Level 1 Level 2 Level 3 Total Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Money market funds ​ $ 54,292 ​ $ — ​ $ — $ 54,292 Commercial paper ​ — ​ 110,227 ​ — 110,227 Corporate debt securities ​ — ​ 10,741 — 10,741 U.S. Treasury and agency securities ​ ​ ​ ​ ​ 57,242 ​ ​ — 57,242 Total financial assets ​ $ 54,292 ​ $ 178,210 $ — $ 232,502

Cash Equivalents and Marketab_2

Cash Equivalents and Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2023
Cash Equivalents and Marketable Securities
Schedule of cash equivalents and marketable securities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, 2023 ​ ​ Amortized ​ Gross Unrealized ​ ​ Cost Gains Losses Fair Value Money market funds ​ $ 46,007 ​ $ — ​ $ — ​ $ 46,007 Commercial paper ​ 87,316 ​ ​ — ​ ​ (17) ​ 87,299 Corporate debt securities ​ ​ 10,877 ​ ​ 5 ​ ​ (12) ​ ​ 10,870 U.S. Treasury and agency securities ​ ​ 79,770 ​ ​ 70 ​ ​ (57) ​ ​ 79,783 Total cash equivalents and marketable securities ​ $ 223,970 ​ $ 75 $ (86) ​ $ 223,959 Classified as: ​ ​ ​ ​ ​ ​ ​ ​ ​ Cash equivalents ​ ​ ​ ​ ​ ​ ​ $ 120,886 Marketable securities ​ ​ ​ ​ ​ ​ ​ 103,073 Total cash equivalents and marketable securities ​ ​ ​ ​ ​ ​ ​ $ 223,959

Balance Sheet Components (Table

Balance Sheet Components (Tables)	3 Months Ended
	Mar. 31, 2023
Balance Sheet Components
Summary of Prepaid Expenses and Other Current Assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ ​ 2023 ​ 2022 Prepaid clinical and research related expenses ​ $ 1,492 ​ $ 2,746 Prepaid insurance ​ ​ 1,401 ​ ​ 1,417 Prepaid license ​ ​ 542 ​ ​ 489 Other prepaid expenses ​ 1,491 ​ 1,018 Other receivable ​ ​ — ​ ​ 42 Prepaid expenses and other current assets ​ $ 4,926 ​ $ 5,712 ​
Summary of Property and Equipment Net	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ ​ 2023 ​ 2022 Laboratory equipment ​ $ 4,831 ​ $ 4,817 Furniture and computer equipment ​ 1,089 ​ 1,089 Leasehold improvements ​ 913 ​ 913 Total property and equipment ​ 6,833 ​ 6,819 Accumulated depreciation ​ (5,492) ​ (5,254) Property and equipment, net ​ $ 1,341 ​ $ 1,565 ​
Schedule of Accrued Expenses and Other Payables	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ December 31, ​ 2023 ​ 2022 Accrued clinical and research related expenses ​ $ 13,108 ​ $ 19,109 Accrued employee related expenses ​ 2,080 ​ 4,967 Accrued professional service fees ​ ​ 1,065 ​ ​ 464 Other ​ 334 ​ 415 Total accrued expenses and other payables ​ $ 16,587 ​ $ 24,955

Equity Plans (Tables)

Equity Plans (Tables)	3 Months Ended
	Mar. 31, 2023
Schedule of activity under equity incentive plans	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted- ​ Weighted- ​ ​ ​ ​ ​ ​ Average ​ Average ​ ​ ​ ​ ​ ​ Exercise ​ Remaining ​ Aggregate ​ ​ Options ​ Price Per ​ Contractual ​ Intrinsic ​ Outstanding Share Life (years) Value (1) ​ ​ ​ ​ ​ ​ ​ ​ ​ (in millions) Balances at December 31, 2022 6,240,509 $ 19.03 ​ ​ ​ Options granted 2,198,750 ​ ​ 12.17 ​ ​ Options exercised (128,722) ​ ​ 13.49 ​ ​ ​ Options forfeited ​ (148,693) ​ ​ 26.21 ​ ​ ​ ​ ​ Balances at March 31, 2023 8,161,844 $ 17.14 ​ 7.74 ​ $ 63.3 Options exercisable – March 31, 2023 ​ 3,935,198 $ 16.82 ​ 6.23 ​ ​ 30.8 Options vested and expected to vest – March 31, 2023 ​ 8,161,844 ​ $ 17.14 7.74 ​ $ 63.3 (1) The aggregate intrinsic values were calculated as the difference between the exercise price of the options and the closing price of the Company’s common stock on March 31, 2023. The calculation excludes options with an exercise price higher than the closing price of the Company’s common stock on March 31, 2023.
Schedule of stock-based compensation expense	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ 2023 2022 Research and development ​ $ 4,582 ​ $ 3,326 General and administrative ​ 3,002 ​ 2,609 Total stock-based compensation expense ​ $ 7,584 ​ $ 5,935
Options to Purchase Common Stock
Black-Scholes option-pricing model assumptions	​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ ​ 2023 ​ 2022 Expected term (in years) 5.27 - 6.02 5.27 - 6.08 Expected volatility 106.3% - 110.1% ​ 97.1% - 98.2% Risk-free interest rate 3.57% - 3.59% ​ 1.64% - 2.13% Dividend yield — —
Restricted stock units
Schedule of activity under equity incentive plans	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ Shares Fair Value Unvested RSUs at December 31, 2022 ​ 637,436 ​ $ 19.29 Granted ​ 396,775 ​ ​ 18.57 Vested ​ (160,884) ​ ​ 15.83 Forfeited ​ (9,215) ​ ​ 20.86 Unvested RSUs at March 31, 2023 ​ 864,112 ​ $ 16.26

Net Loss per Share (Tables)

Net Loss per Share (Tables)	3 Months Ended
	Mar. 31, 2023
Net Loss per Share
Schedule of computation of the basic and diluted net loss per share attributable to common stockholders	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended March 31, ​ 2023 2022 Numerator: ​ ​ ​ ​ ​ ​ Net loss ​ $ (33,725) ​ $ (20,930) Denominator: ​ ​ ​ ​ ​ ​ Weighted-average shares used to compute net loss per common share, basic and diluted ​ 50,573,650 ​ 48,752,548 Net loss per share, basic and diluted ​ $ (0.67) ​ $ (0.43)
Schedule of potentially dilutive securities excluded from diluted net loss per share calculations	​ ​ ​ ​ ​ ​ ​ ​ March 31, ​ 2023 2022 Options to purchase common stock ​ 8,161,844 6,809,610 Common stock warrants ​ 2,750,000 ​ 2,750,000 Restricted stock units ​ 864,112 ​ 606,810 Performance stock units ​ 199,500 ​ 105,500 ESPP shares ​ 24,998 ​ 19,762 Total 12,000,454 10,291,682

Organization and Description _2

Organization and Description of Business - Liquidity (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2023 USD ($) segment	Dec. 31, 2022 USD ($)
Organization and Description of Business
Number of operating segments | segment	1
Net losses from operations since inception
Cash, cash equivalents and marketable securities	$ 230,800
Accumulated deficit	$ (570,480)	$ (536,755)

Summary of Significant Accoun_4

Summary of Significant Accounting Policies - Cash and Cash Equivalents and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Aggregate amounts of cash and cash equivalents and the restricted cash
Cash and cash equivalents	$ 127,686	$ 125,744	$ 98,477
Restricted cash - noncurrent	225	225	225
Total cash reported on condensed consolidated statements of cash flows	$ 127,911	$ 125,969	$ 98,702	$ 123,890

License and Collaboration Agr_3

License and Collaboration Agreement - Narrative (Details) - USD ($)		3 Months Ended
	Jul. 27, 2021	Mar. 31, 2023	Jun. 30, 2022	Mar. 31, 2022	Apr. 30, 2022	Dec. 31, 2021	Mar. 31, 2020	May 07, 2019	Jul. 13, 2017
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
License and collaboration revenue				$ 25,722,000
Recognized revenue from deferred revenue contract liability		$ 0		13,000
Janssen | Services performed for IL-23 receptor antagonist compound research costs and other services
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Reimbursement for services performed			$ 17,900,000
Janssen | License and Collaboration Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Revenue recognized		0
Janssen | License and Collaboration Agreement | Three phase 1 studies of second-generation compounds
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible amount received						$ 7,500,000
Janssen | License and Collaboration Agreement | 3rd patient in the first Phase 2 clinical trial for any second-generation compound for a second indication
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible amount received					$ 25,000,000
Janssen | License and Collaboration Agreement | Phase 3 clinical trial for a second-generation compound for any indication
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upcoming potential development milestones		115,000,000
Janssen | Original Agreement | Upfront cash payment
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upfront payment									$ 50,000,000
Janssen | Restated Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Contract modification, increase (decrease) in adjustment to revenue			200,000
Upfront payment			112,500,000
Development cost payable			6,900,000
Reimbursement for services performed			8,200,000
Maximum percentages royalties on net product sales	10%
Final transaction price			$ 131,700,000	$ 131,500,000
Janssen | Restated Agreement | Second-generation Oral Interleukin ("IL")-23 Receptor Antagonist Development Compound
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible amount received							$ 5,000,000
Janssen | Restated Agreement | License and Collaboration Agreement
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Eligible amount received								$ 25,000,000
Janssen | Restated Agreement | License and Collaboration Agreement | Phase 2 studies for second-generation products
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upcoming potential development milestones		25,000,000
Janssen | Restated Agreement | License and Collaboration Agreement | 3rd patient in the first Phase 2 clinical trial for any second-generation compound for a second indication
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upcoming potential development milestones		10,000,000
Janssen | Restated Agreement | License and Collaboration Agreement | Dosing of the 3rd patient in a Phase 3 clinical trial for a second-generation compound for any indication
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upcoming potential development milestones		50,000,000
Janssen | Restated Agreement | License and Collaboration Agreement | Dosing Of Third Patient In Phase 3 Clinical Trial For Second Generation Compound For A Second Indication [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Upcoming potential development milestones		$ 15,000,000

License and Collaboration Agr_4

License and Collaboration Agreement - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Receivable from collaboration partner - related party
Balance at Beginning of Period		$ 1,566
Additions		25,150
Deductions		(1,566)
Balance at End of Period		25,150
Deferred revenue - related party
Balance at Beginning of Period		1,601
Additions		25,658
Deductions		(26,491)
Balance at End of Period		768
Payable to collaboration partner - related party
Balance at Beginning of Period	$ 69	899
Additions		330
Deductions		(849)
Balance at End of Period	22	$ 380
License and Collaboration Agreement
Receivable from collaboration partner - related party
Balance at Beginning of Period	10
Additions	41
Balance at End of Period	51
Payable to collaboration partner - related party
Balance at Beginning of Period	69
Additions	11
Deductions	(58)
Balance at End of Period	22
Janssen | License and Collaboration Agreement
Deferred revenue - related party
Additions	$ 25,700

Fair Value Measurements (Detail

Fair Value Measurements (Details) - Recurring - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	$ 223,959	$ 232,502
Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	46,007	54,292
Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	87,299	110,227
U.S. Treasury and agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	79,783	57,242
Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	10,870	10,741
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	46,007	54,292
Level 1 [Member] | Money Market Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	46,007	54,292
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	177,952	178,210
Level 2 [Member] | Commercial Paper
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	87,299	110,227
Level 2 [Member] | U.S. Treasury and agency securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	79,783	57,242
Level 2 [Member] | Corporate debt securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total financial assets	$ 10,870	$ 10,741

Cash Equivalents and Marketab_3

Cash Equivalents and Marketable Securities - Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Cash Equivalents and Marketable Securities
Total cash equivalents and marketable securities, Amortized Cost	$ 223,970	$ 232,556
Total cash equivalents and marketable securities, Gross Unrealized Gains	75	27
Total cash equivalents and marketable securities, Gross Unrealized Losses	(86)	(81)
Total cash equivalents and marketable securities, Fair Value	223,959	232,502
U.S. Treasury and agency securities
Cash Equivalents and Marketable Securities
Total cash equivalents and marketable securities, Amortized Cost	79,770	57,251
Total cash equivalents and marketable securities, Gross Unrealized Gains	70	27
Total cash equivalents and marketable securities, Gross Unrealized Losses	(57)	(36)
Total cash equivalents and marketable securities, Fair Value	79,783	57,242
Corporate debt securities
Cash Equivalents and Marketable Securities
Total cash equivalents and marketable securities, Amortized Cost	10,877	10,756
Total cash equivalents and marketable securities, Gross Unrealized Gains	5
Total cash equivalents and marketable securities, Gross Unrealized Losses	(12)	(15)
Total cash equivalents and marketable securities, Fair Value	10,870	10,741
Money Market Funds
Cash Equivalents and Marketable Securities
Total cash equivalents and marketable securities, Amortized Cost	46,007	54,292
Total cash equivalents and marketable securities, Fair Value	46,007	54,292
Commercial Paper
Cash Equivalents and Marketable Securities
Total cash equivalents and marketable securities, Amortized Cost	87,316	110,257
Total cash equivalents and marketable securities, Gross Unrealized Losses	(17)	(30)
Total cash equivalents and marketable securities, Fair Value	$ 87,299	$ 110,227

Cash Equivalents and Marketab_4

Cash Equivalents and Marketable Securities - Classification of Cash Equivalents and Marketable Securities (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Classified as:
Cash equivalents	$ 120,886		$ 120,891
Marketable securities - current	103,073		111,611
Total cash equivalents and marketable securities	$ 223,959		$ 232,502
Contractual maturities
Maximum period of current contractual maturities	1 year		1 year
Realized Gain (loss)	$ 0	$ 0

Balance Sheet Components - Prep

Balance Sheet Components - Prepaid Expenses and Other Current Assets (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid clinical and research related expenses	$ 1,492	$ 2,746
Prepaid insurance	1,401	1,417
Prepaid licenses	542	489
Other prepaid expenses	1,491	1,018
Other receivable		42
Prepaid expenses and other current assets	$ 4,926	$ 5,712

Balance Sheet Components - Prop

Balance Sheet Components - Property and Equipment, Net (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Property and Equipment
Total property and equipment	$ 6,833	$ 6,819
Accumulated depreciation	(5,492)	(5,254)
Property and equipment, net	1,341	1,565
Laboratory equipment
Property and Equipment
Total property and equipment	4,831	4,817
Furniture and computer equipment
Property and Equipment
Total property and equipment	1,089	1,089
Leasehold improvements
Property and Equipment
Total property and equipment	$ 913	$ 913

Balance Sheet Components - Accr

Balance Sheet Components - Accrued Expenses and Other Payables (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Accrued Expenses and Other Payables
Accrued clinical and research related expenses	$ 13,108	$ 19,109
Accrued employee related expenses	2,080	4,967
Accrued professional service fees	1,065	464
Other	334	415
Total accrued expenses and other payables	$ 16,587	$ 24,955

Stockholders' Equity (Details)

Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended				3 Months Ended
	Aug. 31, 2022	Jan. 31, 2022	Oct. 31, 2019	Aug. 31, 2018	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022	Aug. 06, 2018
Stock transactions
Common stock sold					51,440,503		49,339,252
Par value (per share)					$ 0.00001		$ 0.00001
2019 Sales Agreement
Stock transactions
Common stock issued (in shares)		422,367
Maximum aggregate offering price			$ 75
Proceeds from public offering of common stock, net of issuance costs		$ 14.6
2022 Sales Agreement
Stock transactions
Common stock sold					1,749,199
Maximum aggregate offering price	$ 100
Aggregate net proceeds					$ 24.3
Common Stock
Stock transactions
Common stock issued (in shares)					1,749,199	422,367
Common Stock | Private Placement
Stock transactions
Number of warrants exercised					0
Investors | Private Placement
Stock transactions
Aggregate shares of common stock sold				2,750,000
Common stock sold, price per share				$ 8
Net proceeds from sale of common stock				$ 21.7
Warrants issued to purchase common stock, number of shares								2,750,000
Warrants exercisable date				Aug. 08, 2023
$10.00 per share | Investors | Private Placement
Stock transactions
Warrants to purchase common stock (in shares)								1,375,000
Exercise Price (per share)								$ 10
$15.00 per share | Investors | Private Placement
Stock transactions
Warrants to purchase common stock (in shares)								1,375,000
Exercise Price (per share)								$ 15

Equity Plans - Narrative (Detai

Equity Plans - Narrative (Details) - shares	1 Months Ended
	May 31, 2018	Jul. 31, 2016	Mar. 31, 2023
2016 Equity Incentive Plan
Equity Plans
Expiration period		10 years
Number of shares available for issuance			892,905
2018 Inducement Plan
Equity Plans
Expiration period	10 years
Number of shares available for issuance			574,772

Equity Plans - Stock Option Act

Equity Plans - Stock Option Activity (Details) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2023 USD ($) $ / shares shares
Options Outstanding
Options Outstanding, Beginning balance | shares	6,240,509
Options Outstanding, Options granted | shares	2,198,750
Options Outstanding, Options exercised | shares	(128,722)
Options Outstanding, Options forfeited | shares	(148,693)
Options Outstanding, Ending balance | shares	8,161,844
Options Outstanding, Options exercisable | shares	3,935,198
Options Outstanding, Options vested and expected to vest | shares	8,161,844
Weighted-Average Exercise Price Per Share
Weighted-Average Exercise Price Per Share, Beginning balance	$ 19.03
Weighted-Average Exercise Price Per Share, Options granted	12.17
Weighted-Average Exercise Price Per Share, Options exercised	13.49
Weighted-Average Exercise Price Per Share, Options forfeited	26.21
Weighted-Average Exercise Price Per Share, Ending balance	17.14
Weighted-Average Exercise Price Per Share, Options exercisable	16.82
Weighted-Average Exercise Price Per Share, Options vested and expected to vest	$ 17.14
Weighted-Average Remaining Contractual Life (years)
Weighted-Average Remaining Contractual Life (years)	7 years 8 months 26 days
Weighted-Average Remaining Contractual Life (years), Options exercisable	6 years 2 months 23 days
Weighted-Average Remaining Contractual Life (years), Options vested and expected to vest	7 years 8 months 26 days
Aggregate Intrinsic Value
Aggregate Intrinsic Value, Options Outstanding | $	$ 63.3
Aggregate Intrinsic Value, Options exercisable | $	30.8
Aggregate Intrinsic Value, Options vested and expected to vest | $	$ 63.3
Options, weighted-average grant-date fair value	$ 10.05

Equity Plans - Stock Options Va

Equity Plans - Stock Options Valuation Assumptions (Details) - Options to Purchase Common Stock	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Equity Plans
Expected volatility, Minimum	106.30%	97.10%
Expected volatility, Maximum	110.10%	98.20%
Risk-free interest rate, Minimum	3.57%	1.64%
Risk-free interest rate, Maximum	3.59%	2.13%
Dividend yield	0%	0%
Expected Volatility, Percentage Of Mix Allocated To Peer Companies			25%
Expected Volatility, Percentage Of Mix Allocated To Entity Stock Price			75%
Minimum
Equity Plans
Expected term (in years)	5 years 3 months 7 days	5 years 3 months 7 days
Maximum
Equity Plans
Expected term (in years)	6 years 7 days	6 years 29 days

Equity Plans - Restricted and P

Equity Plans - Restricted and Performance Stock Units - (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Restricted stock units
Number of Shares
Number of shares, Unvested, Beginning balance	637,436
Number of shares, Granted	396,775
Number of shares, Vested	(160,884)
Number of Shares, Forfeited	(9,215)
Number of shares, Unvested, Ending balance	864,112	637,436
Weighted-Average Grant Date Fair Value
Weighted-Average Grant Date Fair Value, Unvested, Beginning balance	$ 19.29
Weighted-Average Grant Date Fair Value, Granted	18.57
Weighted-Average Grant Date Fair Value, Vested	15.83
Weighted-Average Grant Date Fair Value, Forfeited	20.86
Weighted-Average Grant Date Fair Value, Unvested, Ending balance	$ 16.26	$ 19.29
Performance Stock Units
Equity Plans
Vesting percentage of requisite service period	100%	100%
Number of Shares
Number of shares, Unvested, Beginning balance	199,500
Number of shares, Unvested, Ending balance	199,500	199,500
Weighted-Average Grant Date Fair Value
Weighted-Average Grant Date Fair Value, Unvested, Beginning balance	$ 14.59
Weighted-Average Grant Date Fair Value, Unvested, Ending balance	$ 14.59	$ 14.59
Aggregate fair value of restricted stock units that vested	$ 2.9

Equity Plans - Performance Stoc

Equity Plans - Performance Stock Units (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Equity Plans
Stock-based compensation	$ 7,584,000	$ 5,935,000
Performance Stock Units
Equity Plans
Vesting percentage of requisite service period	100%		100%
Fair value of stock units	$ 2,900,000
Stock-based compensation	$ 0

Equity Plans - Employee Stock P

Equity Plans - Employee Stock Purchase Plan 2016 ESPP (Details) - 2016 Employee Stock Purchase Plan - shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Equity Plans
Maximum payroll deduction for share purchases (as a percent)	15%
Purchase price of stock (as a percent)	85%
Shares issued in period		68,605
Number of shares available for issuance	1,486,685

Equity Plans - Stock-based Comp

Equity Plans - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 7,584	$ 5,935
Total unrecognized stock-based compensation costs related to stock options	$ 66,800
Period of unrecognized stock-based compensation costs to be recognized	2 years 8 months 12 days
Research and Development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 4,582	3,326
General and Administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation expense	$ 3,002	$ 2,609

Net Loss per Share - Computatio

Net Loss per Share - Computation (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Numerator:
Net loss	$ (33,725)	$ (20,930)
Denominator:
Weighted-average shares used to compute net loss per common share, Basic	50,573,650	48,752,548
Weighted-average shares used to compute net loss per common share, Diluted	50,573,650	48,752,548
Net loss per share, basic	$ (0.67)	$ (0.43)
Net loss per share, diluted	$ (0.67)	$ (0.43)

Net Loss per Share - Antidiluti

Net Loss per Share - Antidilutive Securities (Details) - shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Potentially dilutive securities have been excluded from diluted net loss per share calculations
Anti-dilutive securities (in shares)	12,000,454	10,291,682
Options to Purchase Common Stock
Potentially dilutive securities have been excluded from diluted net loss per share calculations
Anti-dilutive securities (in shares)	8,161,844	6,809,610
Common stock warrants
Potentially dilutive securities have been excluded from diluted net loss per share calculations
Anti-dilutive securities (in shares)	2,750,000	2,750,000
Restricted stock units
Potentially dilutive securities have been excluded from diluted net loss per share calculations
Anti-dilutive securities (in shares)	864,112	606,810
Performance Stock Units
Potentially dilutive securities have been excluded from diluted net loss per share calculations
Anti-dilutive securities (in shares)	199,500	105,500
ESPP shares
Potentially dilutive securities have been excluded from diluted net loss per share calculations
Anti-dilutive securities (in shares)	24,998	19,762

Subsequent Event (Details)

Subsequent Event (Details) - Subsequent Event $ / shares in Units, $ in Millions	1 Months Ended
	Apr. 30, 2023 USD ($) $ / shares shares
Subsequent Event [Line Items]
Common stock sold, price per share | $ / shares	$ 20
Common stock issued (in shares) | shares	5,000,000
Net proceeds, after deducting issuance costs | $	$ 107.7
Underwriter share
Subsequent Event [Line Items]
Common stock sold, price per share | $ / shares	$ 20
Common stock issued (in shares) | shares	750,000