Satsuma Pharmaceuticals (STSA) 10-Q 10 May 22 2022 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2022	May 06, 2022
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2022
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Entity Registrant Name	Satsuma Pharmaceuticals, Inc.
Entity Central Index Key	0001692830
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	true
Entity Ex Transition Period	false
Entity File Number	001-39041
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	81-3039831
Entity Address, Address Line One	400 Oyster Point Boulevard
Entity Address, Address Line Two	Suite 221
Entity Address, City or Town	South San Francisco
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94080
City Area Code	650
Local Phone Number	410-3200
Document Quarterly Report	true
Document Transition Report	false
Title of 12(b) Security	Common stock, par value $0.0001
Trading Symbol	STSA
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding		31,545,564

Condensed Balance Sheets (Unaud

Condensed Balance Sheets (Unaudited) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Assets
Cash and cash equivalents	$ 21,359	$ 15,835
Short-term marketable securities	57,153	77,315
Prepaid expenses and other current assets	5,571	6,698
Total current assets	84,083	99,848
Property and equipment, net	6,739	6,792
Operating lease right-of-use asset	244
Long-term marketable securities	2,085	2,620
Other non-current assets	521	572
Total assets	93,672	109,832
Liabilities
Accounts payable	1,799	1,469
Accrued and other current liabilities	4,067	5,943
Operating lease liability	136
Current portion of long-term debt	583	1,080
Total current liabilities	6,585	8,492
Operating lease liability, net of current portion	104
Total liabilities	6,689	8,492
Commitments and contingencies (Note 8)
Stockholders’ equity
Preferred stock, $0.0001 par value, 10,000,000 shares authorized as of March 31, 2022 and December 31, 2021; no shares issued and outstanding as of March 31, 2022 and December 31, 2021
Common stock, $0.0001 par value, 300,000,000 shares authorized as of March 31, 2022 and December 31, 2021; 31,545,564 shares issued and outstanding as of March 31, 2022 and December 31, 2021	3	3
Additional paid-in-capital	244,354	243,115
Accumulated other comprehensive loss	(121)	(42)
Accumulated deficit	(157,253)	(141,736)
Total stockholders’ equity	86,983	101,340
Total liabilities and stockholders’ equity	$ 93,672	$ 109,832

Condensed Balance Sheets (Una_2

Condensed Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Mar. 31, 2022	Dec. 31, 2021
Statement Of Financial Position [Abstract]
Preferred stock, par value	$ 0.0001	$ 0.0001
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 (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	31,545,564	31,545,564
Common stock, shares outstanding	31,545,564	31,545,564

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating expenses
Research and development	$ 11,556	$ 7,156
General and administrative	3,990	3,294
Total operating expenses	15,546	10,450
Loss from operations	(15,546)	(10,450)
Interest income	40	50
Interest expense	(11)	(57)
Net loss	(15,517)	(10,457)
Unrealized loss on marketable securities	(79)	(26)
Comprehensive loss	$ (15,596)	$ (10,483)
Net loss per share attributable to common stockholders, basic and diluted	$ (0.49)	$ (0.48)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted	31,545,564	21,975,407

Condensed Statements of Stockho

Condensed Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Beginning balance at Dec. 31, 2020	$ 71,936	$ 2	$ 162,469	$ 29	$ (90,564)
Beginning balance, Shares at Dec. 31, 2020		17,436,978
Issuance of common stock upon exercise of stock options	8		8
Issuance of common stock upon exercise of stock options, Shares		7,932
Issuance of common stock in private placement financing, net of issuance costs of $4,785	75,215	$ 1	75,214
Issuance of common stock in private placement financing, net of issuance costs of $4,785, Shares		14,084,507
Stock-based compensation	1,469		1,469
Net loss	(10,457)				(10,457)
Other comprehensive income (loss)	(26)			(26)
Ending balance at Mar. 31, 2021	138,145	$ 3	239,160	3	(101,021)
Ending Balance, Shares at Mar. 31, 2021		31,529,417
Beginning balance at Dec. 31, 2021	101,340	$ 3	243,115	(42)	(141,736)
Beginning balance, Shares at Dec. 31, 2021		31,545,564
Stock-based compensation	1,239		1,239
Net loss	(15,517)				(15,517)
Other comprehensive income (loss)	(79)			(79)
Ending balance at Mar. 31, 2022	$ 86,983	$ 3	$ 244,354	$ (121)	$ (157,253)
Ending Balance, Shares at Mar. 31, 2022		31,545,564

Condensed Statements of Stock_2

Condensed Statements of Stockholders' Equity (Parenthetical) (Unaudited) $ in Thousands	3 Months Ended
	Mar. 31, 2021USD ($)
Statement Of Stockholders Equity [Abstract]
Common stock issuance costs	$ 4,785

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities
Net loss	$ (15,517)	$ (10,457)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation	92	80
Amortization of operating lease right-of-use asset	37
Non-cash interest expense, and amortization of debt discount and issuance costs	3	17
Amortization of premiums / (accretion of discounts), net on marketable securities	253	53
Stock-based compensation	1,239	1,469
Changes in assets and liabilities
Prepaid expenses and other assets	1,178	2,394
Accounts payable	339	(1,578)
Accrued and other current liabilities	(1,900)	(461)
Operating lease liabilities, net	(41)
Other non-current liabilities		(2)
Net cash used in operating activities	(14,317)	(8,485)
Cash flows from investing activities
Purchases of marketable securities	(1,989)	(7,869)
Proceeds from maturities of marketable securities	22,354	8,800
Purchases of property and equipment	(24)	(1,275)
Net cash provided by (used in) investing activities	20,341	(344)
Cash flows from financing activities
Repayment of debt	(500)	(500)
Proceeds from private placement financing, net of issuance costs		75,215
Proceeds from exercise of common stock options		8
Net cash (used in) provided by financing activities	(500)	74,723
Net increase in cash and cash equivalents	5,524	65,894
Cash and cash equivalents
Cash and cash equivalents, at beginning of period	15,835	36,326
Cash and cash equivalents, at end of period	21,359	102,220
Supplemental disclosure of cash flow information:
Cash paid for interest	11	43
Supplemental non-cash investing and financing activities:
Operating lease right-of-use asset recorded on the adoption of ASC 842	80
Operating lease right-of-use assets obtained in exchange for new lease liabilities	201
Purchases of property and equipment in accounts payable and accrued and other current liabilities	$ 39	$ 63

Organization and Summary of Sig

Organization and Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Organization and Summary of significant Accounting Policies	Note 1. Organization and Summary of Significant Accounting Policies Description of the Business Satsuma Pharmaceuticals, Inc. (the “Company”) is a clinical-stage biopharmaceutical company developing a novel therapeutic for the acute treatment of migraine. The Company’s product candidate, STS101, is a drug-device combination of a proprietary dry-powder formulation of dihydroergotamine mesylate, or DHE, which can be quickly and easily self-administered by a proprietary pre-filled, single-use, nasal delivery device. The Company, headquartered in South San Francisco, was incorporated in 2016 in the state of Delaware. Private Placement In February 2021, the Company entered into a Securities Purchase Agreement with certain purchasers, pursuant to which the Company agreed to sell and issue to certain purchasers an aggregate of 14,084,507 shares of its common stock at a per share purchase price of $5.68, the closing price of its common stock on the Nasdaq Global Market on February 26, 2021, for gross proceeds of $80.0 million (“Private Placement”). The Private Placement closed in March 2021 and the Company received $75.2 million in net proceeds after deducting commissions and offering expenses. Liquidity The Company is subject to risks and uncertainties common to early-stage companies in the biopharmaceutical industry, including, but not limited to, risks of clinical delays or failure, development by competitors of new technological innovations, protection of proprietary technology, dependence on key personnel, reliance on contract manufacturing organizations (“CMOs”), contract research organizations (“CROs”), compliance with government regulations and the need to obtain additional financing to fund operations. STS101 is an investigational product candidate that will require additional clinical development prior to any submission for regulatory approval and commercialization, if approved. These efforts require significant amounts of additional capital, adequate personnel, infrastructure, and extensive compliance and reporting. The Company has incurred significant losses and negative cash flows from operations in all periods since its inception and had an accumulated deficit of $157.3 million as of March 31, 2022. The Company has historically financed its operations primarily through its initial public offering (“IPO”), and private placements of its equity securities and borrowings under its long-term debt facility. The Company has no products approved for sale, and the Company has not generated any revenue since its inception. The Company expects to incur significant additional operating losses over at least the next several years. There can be no assurance that in the event the Company requires additional financing, such financing will be available on terms which are favorable or at all. Failure to generate sufficient cash flows from operations or raise additional capital to support its operations would have a material adverse effect on the Company’s ability to achieve its intended business objectives. As of March 31, 2022, the Company had cash, cash equivalents and marketable securities of $80.6 million. The Company’s management believes that the Company’s current cash, cash equivalents and marketable securities will be sufficient to fund its planned operations for at least 12 months from the date of the issuance of these unaudited interim condensed financial statements as of and for the three months ended March 31, 2022. Basis of Presentation The unaudited interim condensed financial statements and accompanying notes have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) , as defined by the Financial Accounting Standards Board, or the FASB Unaudited Interim Financial Information The accompanying condensed balance sheet as of March 31, 2022, the condensed statements of operations and comprehensive loss, the condensed statements of stockholders’ equity and the condensed statements of cash flows for the three months ended March 31, 2022 and 2021 are unaudited. The unaudited interim condensed financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of March 31, 2022 and the results of its operations and its cash flows for the three months ended March 31, 2022 and 2021. The financial data and other information disclosed in these notes related to the three months ended March 31, 2022 and 2021 are also unaudited. The results for the three months ended March 31, 2022 are not necessarily indicative of results to be expected for the year ending December 31, 2022, any other interim periods, or any future year or period. The balance sheet as of December 31, 20 2 1 included herein was derived from the audited financial statements as of that date. Certain disclosures have been condensed or omitted from the unaudited interim condensed financial statements. The accompanying interim unaudited condensed financial statements should be read in conjunction with the audited financial statements and the related notes thereto for the year ended December 31, 2021, which are included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2021 filed with the Securities and Exchange Commission, or the SEC, on March 15, 2022. Use of Estimates The preparation of unaudited interim condensed financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the unaudited interim condensed financial statements and the reported amounts of income and expenses during the reporting period. Such estimates include the accrual of research and development expenses, useful lives of property and equipment and the fair value of stock-based awards. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the impact of the COVID-19 pandemic which may delay the enrollment of subjects for our clinical trials and may disrupt our supply chain for development and manufacturing activities, and adjust those estimates and assumptions when facts and circumstances dictate. Actual results could differ materially from those estimates and assumptions. Concentration of Credit Risk The Company has no significant off-balance sheet concentrations of credit risk. Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash, cash equivalents and marketable securities. Substantially all the Company’s cash is held by one financial institution that management believes to be of high credit quality. Such deposits may, at times, exceed federally insured limits. The Company invests its cash equivalents in marketable securities and money market funds. The Company has not experienced any credit losses on its deposits of cash or cash equivalents. Leases In February 2016, the FASB issued Accounting Standards Update No. 2016-02 (Topic 842) "Leases." Leases Leases (ASC 842): Targeted Improvements The reported results for the three months ended March 31, 2022 reflect the application of ASC 842, while the comparative information has not been restated and continues to be reported under the related lease accounting standards in effect for those periods. The adoption of this update represents a change in accounting principle and resulted in the recognition of right-of-use ("ROU") assets and operating lease liabilities. The Company elected the package of practical expedients, which permits the Company not to reassess prior conclusions about lease identification, lease classification and initial direct costs incurred. The Company also elected the practical expedient to combine lease and non-lease components when determining the ROU asset and lease liability, as well as the practical expedient to exclude leases with an initial term of 12 months or less. The primary effect of adopting this standard relates to the recognition of operating leases on the condensed balance sheets and providing additional disclosures about the Company’s leasing activities. The Company adopted ASC 842 effective January 1, 2022 using a modified retrospective method and did not restate comparative periods. The Company recognized ROU assets of $0.1 million and lease liabilities of $0.1 million for its operating leases as of January 1, 2022. The adoption of these ASUs did not have any impact on the condensed statements of operations and comprehensive loss and condensed statements of cash flows. See Note 8 for more information related to the Company’s lease obligations. Recent Accounting Pronouncements New Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326) , to provide financial statement users with more useful information about expected credit losses, which was subsequently updated by ASU 2019-04, Codification Improvements to Topic 326, Financial Instrument - Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments, and ASU 2019-05, Financial Instruments - Credit Losses (Topic 326): Targeted Transition Relief. The amendment updates the guidance for measuring and recording credit losses on financial assets measured at amortized cost by replacing the “incurred loss” model with an “expected loss” model. Accordingly, these financial assets will be presented at the net amount expected to be collected. The amendment also requires that credit losses related to available-for-sale debt securities be recorded as an allowance through net income rather than reducing the carrying amount under the current, other-than-temporary-impairment model. In November 2019, the FASB issued ASU No. 2019-10, according to which, the new standard is effective for public business entities that meet the definition of an SEC filer, excluding entities eligible to be smaller reporting companies (“SRC”) as defined by the SEC, for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. For all other entities, the new standard is effective for fiscal years beginning after December 15, 2022, and interim periods within that fiscal year. Early adoption is permitted. The Company is a SRC for fiscal year 20 21 . For the Company this standard is effective for fiscal years beginning after December 15, 2022, and interim periods within that fiscal year. The adoption of this standard is not expected to have a material impact on the Company’s financial statements and related disclosures .

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	2. Fair Value Measurements The Company applies fair value accounting for all financial assets and liabilities and non-financial assets and liabilities that are recognized or disclosed at fair value in the unaudited interim condensed financial statements on a recurring basis. Fair value is 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, a three-tier fair value hierarchy has been established, which prioritizes the inputs used in measuring fair value as follows: Level 1—Observable inputs, such as quoted prices in active markets for identical assets or liabilities at the measurement date. Level 2—Observable inputs other than Level 1 prices such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 3—Unobservable inputs which reflect management’s best estimate of what market participants would use in pricing the asset or liability at the measurement date. Consideration is given to the risk inherent in the valuation technique and the risk inherent in the inputs to the model. In determining fair value, the Company utilizes valuation techniques that maximize the use of observable inputs and minimize the use of unobservable inputs to the extent possible as well as considers counterparty credit risk in its assessment of fair value. As of March 31, 2022, financial assets measured and recognized at fair value were as follows (in thousands): Fair Value Measurements at March 31, 2022 Level 1 Level 2 Level 3 Total Assets U.S. government bonds $ 6,610 $ — $ — $ 6,610 Foreign government agency bonds (1) — 6,507 — 6,507 Corporate bonds — 31,034 — 31,034 Asset backed securities — 15,087 — 15,087 Marketable securities 6,610 52,628 — 59,238 Money market funds (2) 21,334 — — 21,334 Total fair value of assets $ 27,944 $ 52,628 $ — $ 80,572 (1) Consists of short-term agency bonds of Asian Development Bank and International Bank for Reconstruction and Development. (2) Included in cash and cash equivalents on the balance sheet. Fair Value Measurements at March 31, 2022 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimate Fair Value Assets U.S. government bonds $ 6,640 $ — $ (30 ) $ 6,610 Foreign government agency bonds (1) 6,513 — (6 ) 6,507 Corporate bonds 31,085 — (51 ) 31,034 Asset backed securities 15,121 — (34 ) 15,087 Marketable securities 59,359 — (121 ) 59,238 Money market funds (2) 21,334 — — 21,334 Total fair value of assets $ 80,693 $ — $ (121 ) $ 80,572 (1) Consists of short-term agency bonds of Asian Development Bank and International Bank for Reconstruction and Development. (2) Included in cash and cash equivalents on the balance sheet. As of December 31, 2021, financial assets measured and recognized at fair value were as follows (in thousands): Fair Value Measurements at December 31, 2021 Level 1 Level 2 Level 3 Total Assets U.S. government bonds $ 4,667 $ — $ — $ 4,667 Foreign government agency bonds (1) — 6,526 — 6,526 Corporate bonds — 49,989 — 49,989 Asset backed securities — 18,753 — 18,753 Marketable securities 4,667 75,268 — 79,935 Money market funds (2) 15,809 — — 15,809 Total fair value of assets $ 20,476 $ 75,268 $ — $ 95,744 (1) Consists of short-term agency bonds of Asian Development Bank and International Bank for Reconstruction and Development. (2) Included in cash and cash equivalents on the balance sheet. Fair Value Measurements at December 31, 2021 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimate Fair Value Assets U.S. government bonds $ 4,670 $ — $ (3 ) $ 4,667 Foreign government agency bonds (1) 6,530 — (4 ) 6,526 Corporate bonds 50,008 — (19 ) 49,989 Asset backed securities 18,769 — (16 ) 18,753 Marketable securities 79,977 — (42 ) 79,935 Money market funds (2) 15,809 — — 15,809 Total fair value of assets $ 95,786 $ — $ (42 ) $ 95,744 (1) Consists of short-term agency bonds of Asian Development Bank and International Bank for Reconstruction and Development. (2) Included in cash and cash equivalents on the balance sheet. There were no financial liabilities measured and recognized at fair value as of March 31, 2022 and December 31, 2021. As of March 31, 2022, the fair value of the Term Loan (as defined in Note 4 below) approximates the carrying amount of the loan as the Term Loan bears floating interest rate that approximates the market rate.

Balance Sheet Components

Balance Sheet Components	3 Months Ended
	Mar. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Components	3. Balance Sheet Components Property and Equipment, Net Depreciation is computed using the straight-line method. Depreciation expense was $0.1 million and $0.1 million for the three months ended March 31, 2022 and 2021, respectively. Accumulated depreciation as of , 2022 and December 31, 2021 was $0.7 million and $0.6 million, respectively. Accrued and Other Current Liabilities Accrued and other current liabilities consisted of the following (in thousands): March 31, December 31, 2022 2021 Accrued salaries and benefits $ 919 $ 2,117 Accrued research and development expenses 2,728 3,396 Accrued professional services 364 361 Other 56 69 Total $ 4,067 $ 5,943

Long-Term Debt

Long-Term Debt	3 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Long-Term Debt	4 . Long-Term Debt On October 26, 2018, the Company entered into a Loan and Security Agreement (the “Loan Agreement”) with Silicon Valley Bank. The Loan Agreement provides for loan advances of up to $10.0 million. The first advance (the “Term A Loan”) of $5.0 million was available for draw down by the Company as of the effective date of the Loan Agreement. The remaining $5.0 million under the facility was never drawn down and is no longer available for draw. Interest on the loan advances is payable monthly at a floating per annum rate equal to the greater of 1.5% above the prime rate or 6.5%. Upon the occurrence of an event of default, interest will increase to 5.0% above the rate that is otherwise applicable. The maturity date of the loan advances is May 1, 2022. The effective interest rate of the Term Loan approximates its stated interest rates. As of March 31, 2021, the future contractual maturities of debt by fiscal year are as follows (in thousands): 2022 (remaining nine months) $ 333 Total future maturities of debt $ 333 As of March 31, 2022, the term loan advances, net of debt discount and debt issuance costs, were $0.6 million and are included in current portion of long-term debt on the Company’s condensed balance sheet. The Company accreted the final payment due at maturity using the effective interest rate method. The accrued liabilities related to the accretion of the final payment were $0.2 million as of March 31, 2022 and $0.2 million as of December 31, 2021 and were included in the current portion of long-term debt on the Company’s condensed balance sheets, respectively.

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2022
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	5. Stock-Based Compensation A summary of stock option activity for the three months ended March 31, 2022 is set forth below: Outstanding Options Shares Available for Grant Number of Shares Weighted Average Exercise Price Weighted- Average Remaining Contractual Term (Years) Balance, January 1, 2022 1,493,893 3,202,588 $ 9.14 7.73 Additional shares authorized 1,261,822 Options granted (63,000 ) 63,000 $ 4.36 9.88 Options cancelled 50,685 (50,685 ) $ 9.28 Balance, March 31, 2022 2,743,400 3,214,903 $ 9.04 7.65 Exercisable as of March 31, 2022 1,784,053 $ 8.46 7.09 Vested and expected to vest, March 31, 2022 3,214,903 $ 9.04 7.65 The weighted-average grant-date fair value of options granted during the three months ended March 31, 2022 and 2021 was $3.42 and $4.16 per share, respectively. As of March 31, 2022, the total unrecognized stock-based compensation expense for stock options was $8.6 million, which is expected to be recognized over a weighted-average period of 2.0 years. The total fair value of options vested for the three months ended March 31, 2022 and 2021 was $1.2 million and $2.9 million, respectively. 2019 Share Purchase Plan In September 2019, the Company adopted the 2019 Employee Share Purchase Plan (“ESPP”), which became effective on the day of effectiveness of the Company’s registration statement on Form S-1 filed in connection with its IPO . As of March 31, 2022, 792,731 shares under the ESPP remain available for purchase. The offering period and purchase period is determined by the board of directors (the “Board”). The Board authorized a new offering period of six months beginning December 16, 2021 through June 15, 2022. Stock-Based Compensation Expense Total stock-based compensation expense recorded related to options granted to employees and non-employees was as follows (in thousands): Three Months March 31, 2022 2021 Research and development $ 436 $ 444 General and administrative 803 1,025 $ 1,239 $ 1,469

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Stockholders	3 Months Ended
	Mar. 31, 2022
Earnings Per Share [Abstract]
Net Loss Per Share Attributable to Common Stockholders	6 . Net Loss Per Share Attributable to Common Stockholders The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders (in thousands, except share and per share data): Three Months Ended March 31, 2022 2021 Numerator: Net loss attributable to common stockholders $ (15,517 ) $ (10,457 ) Denominator: Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted 31,545,564 21,975,407 Net loss per share attributable to common stockholders, basic and diluted $ (0.49 ) $ (0.48 ) The following outstanding shares of potentially dilutive securities were excluded from the computation of diluted net loss per share attributable to common stockholders for the period presented because including them would have been antidilutive: March 31, 2022 2021 Options to purchase common stock 3,214,903 3,157,527 Shares committed under ESPP 28,746 — Total 3,243,649 3,157,527

Related Party Transaction

Related Party Transaction	3 Months Ended
	Mar. 31, 2022
Related Party Transactions [Abstract]
Related Party Transactions	7 . Related Party Transactions Two existing stockholders of the Company that are affiliated with directors of the Company purchased a total of 2,464,788 shares of the Company’s common stock, with an aggregate purchase price of $14.0 million, in the Private Placement.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2022
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	8 . Commitments and Contingencies Operating Leases Rent expense for the three months ended March 31, 2021 was $0.1 million. Operating lease cost consists of the following (in thousands): Three Months Ended March 31, 2022 Operating lease cost $ 39 Short-term lease cost 33 Total lease cost $ 72 Future minimum lease payments under non-cancelable operating leases as of December 31, 2021 were as follows (in thousands): Operating Leases 2022 $ 201 Total minimum lease payments $ 201 The maturities of operating lease liabilities as of March 31, 2022 are as follows (in thousands): March 31, 2022 2022 (remaining nine months) $ 106 2023 141 Total undiscounted lease payments 247 Less: imputed interest 7 Total operating lease liability 240 Less: current portion 136 Operating lease liability, net of current portion $ 104 As of March 31, 2022, the remaining term for the operating lease in North Carolina was 1.3 years, and the discount rate used to measure the lease liability for such operating lease upon recognition was 4.9%. During the three months ended March 31, 2022, cash paid for amounts included in operating lease liabilities of less than $0.1 million was included in cash flows from operating activities on the condensed statements of cash flows.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	9 . Income Taxes For the three months ended March 31, 2022 and 2021, the Company did not record an income tax provision. The U.S. federal and California deferred tax assets generated from the Company’s net operating losses have been fully reserved, as the Company believes it is more likely than not the benefit will not be realized.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2022
Subsequent Events [Abstract]
Subsequent Events	1 0 . Subsequent Events For the purposes of the unaudited interim condensed financial statements as of March 31, 2022 and for the three months ended, the Company has evaluated the subsequent events through May 10, 2022, the date the unaudited interim condensed financial statements were issued.

Organization and Summary of S_2

Organization and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2022
Accounting Policies [Abstract]
Description of the Business	Description of the Business Satsuma Pharmaceuticals, Inc. (the “Company”) is a clinical-stage biopharmaceutical company developing a novel therapeutic for the acute treatment of migraine. The Company’s product candidate, STS101, is a drug-device combination of a proprietary dry-powder formulation of dihydroergotamine mesylate, or DHE, which can be quickly and easily self-administered by a proprietary pre-filled, single-use, nasal delivery device. The Company, headquartered in South San Francisco, was incorporated in 2016 in the state of Delaware.
Private Placement	Private Placement In February 2021, the Company entered into a Securities Purchase Agreement with certain purchasers, pursuant to which the Company agreed to sell and issue to certain purchasers an aggregate of 14,084,507 shares of its common stock at a per share purchase price of $5.68, the closing price of its common stock on the Nasdaq Global Market on February 26, 2021, for gross proceeds of $80.0 million (“Private Placement”). The Private Placement closed in March 2021 and the Company received $75.2 million in net proceeds after deducting commissions and offering expenses.
Liquidity	Liquidity The Company is subject to risks and uncertainties common to early-stage companies in the biopharmaceutical industry, including, but not limited to, risks of clinical delays or failure, development by competitors of new technological innovations, protection of proprietary technology, dependence on key personnel, reliance on contract manufacturing organizations (“CMOs”), contract research organizations (“CROs”), compliance with government regulations and the need to obtain additional financing to fund operations. STS101 is an investigational product candidate that will require additional clinical development prior to any submission for regulatory approval and commercialization, if approved. These efforts require significant amounts of additional capital, adequate personnel, infrastructure, and extensive compliance and reporting. The Company has incurred significant losses and negative cash flows from operations in all periods since its inception and had an accumulated deficit of $157.3 million as of March 31, 2022. The Company has historically financed its operations primarily through its initial public offering (“IPO”), and private placements of its equity securities and borrowings under its long-term debt facility. The Company has no products approved for sale, and the Company has not generated any revenue since its inception. The Company expects to incur significant additional operating losses over at least the next several years. There can be no assurance that in the event the Company requires additional financing, such financing will be available on terms which are favorable or at all. Failure to generate sufficient cash flows from operations or raise additional capital to support its operations would have a material adverse effect on the Company’s ability to achieve its intended business objectives. As of March 31, 2022, the Company had cash, cash equivalents and marketable securities of $80.6 million. The Company’s management believes that the Company’s current cash, cash equivalents and marketable securities will be sufficient to fund its planned operations for at least 12 months from the date of the issuance of these unaudited interim condensed financial statements as of and for the three months ended March 31, 2022.
Basis of Presentation	Basis of Presentation The unaudited interim condensed financial statements and accompanying notes have been prepared in accordance with U.S. generally accepted accounting principles (“U.S. GAAP”) , as defined by the Financial Accounting Standards Board, or the FASB
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying condensed balance sheet as of March 31, 2022, the condensed statements of operations and comprehensive loss, the condensed statements of stockholders’ equity and the condensed statements of cash flows for the three months ended March 31, 2022 and 2021 are unaudited. The unaudited interim condensed financial statements have been prepared on the same basis as the audited annual financial statements and, in the opinion of management, reflect all adjustments, which include only normal recurring adjustments, necessary for the fair statement of the Company’s financial position as of March 31, 2022 and the results of its operations and its cash flows for the three months ended March 31, 2022 and 2021. The financial data and other information disclosed in these notes related to the three months ended March 31, 2022 and 2021 are also unaudited. The results for the three months ended March 31, 2022 are not necessarily indicative of results to be expected for the year ending December 31, 2022, any other interim periods, or any future year or period. The balance sheet as of December 31, 20 2 1 included herein was derived from the audited financial statements as of that date. Certain disclosures have been condensed or omitted from the unaudited interim condensed financial statements. The accompanying interim unaudited condensed financial statements should be read in conjunction with the audited financial statements and the related notes thereto for the year ended December 31, 2021, which are included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2021 filed with the Securities and Exchange Commission, or the SEC, on March 15, 2022.
Use of Estimates	Use of Estimates The preparation of unaudited interim condensed financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the unaudited interim condensed financial statements and the reported amounts of income and expenses during the reporting period. Such estimates include the accrual of research and development expenses, useful lives of property and equipment and the fair value of stock-based awards. The Company evaluates its estimates and assumptions on an ongoing basis using historical experience and other factors, including the impact of the COVID-19 pandemic which may delay the enrollment of subjects for our clinical trials and may disrupt our supply chain for development and manufacturing activities, and adjust those estimates and assumptions when facts and circumstances dictate. Actual results could differ materially from those estimates and assumptions.
Concentration of Credit Risk	Concentration of Credit Risk The Company has no significant off-balance sheet concentrations of credit risk. Financial instruments that potentially subject the Company to a concentration of credit risk consist of cash, cash equivalents and marketable securities. Substantially all the Company’s cash is held by one financial institution that management believes to be of high credit quality. Such deposits may, at times, exceed federally insured limits. The Company invests its cash equivalents in marketable securities and money market funds. The Company has not experienced any credit losses on its deposits of cash or cash equivalents.
Leases	Leases In February 2016, the FASB issued Accounting Standards Update No. 2016-02 (Topic 842) "Leases." Leases Leases (ASC 842): Targeted Improvements The reported results for the three months ended March 31, 2022 reflect the application of ASC 842, while the comparative information has not been restated and continues to be reported under the related lease accounting standards in effect for those periods. The adoption of this update represents a change in accounting principle and resulted in the recognition of right-of-use ("ROU") assets and operating lease liabilities. The Company elected the package of practical expedients, which permits the Company not to reassess prior conclusions about lease identification, lease classification and initial direct costs incurred. The Company also elected the practical expedient to combine lease and non-lease components when determining the ROU asset and lease liability, as well as the practical expedient to exclude leases with an initial term of 12 months or less. The primary effect of adopting this standard relates to the recognition of operating leases on the condensed balance sheets and providing additional disclosures about the Company’s leasing activities. The Company adopted ASC 842 effective January 1, 2022 using a modified retrospective method and did not restate comparative periods. The Company recognized ROU assets of $0.1 million and lease liabilities of $0.1 million for its operating leases as of January 1, 2022. The adoption of these ASUs did not have any impact on the condensed statements of operations and comprehensive loss and condensed statements of cash flows. See Note 8 for more information related to the Company’s lease obligations.
Recent Accounting Pronouncements	Recent Accounting Pronouncements New Accounting Pronouncements Not Yet Adopted In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326) , to provide financial statement users with more useful information about expected credit losses, which was subsequently updated by ASU 2019-04, Codification Improvements to Topic 326, Financial Instrument - Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments, and ASU 2019-05, Financial Instruments - Credit Losses (Topic 326): Targeted Transition Relief. The amendment updates the guidance for measuring and recording credit losses on financial assets measured at amortized cost by replacing the “incurred loss” model with an “expected loss” model. Accordingly, these financial assets will be presented at the net amount expected to be collected. The amendment also requires that credit losses related to available-for-sale debt securities be recorded as an allowance through net income rather than reducing the carrying amount under the current, other-than-temporary-impairment model. In November 2019, the FASB issued ASU No. 2019-10, according to which, the new standard is effective for public business entities that meet the definition of an SEC filer, excluding entities eligible to be smaller reporting companies (“SRC”) as defined by the SEC, for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. For all other entities, the new standard is effective for fiscal years beginning after December 15, 2022, and interim periods within that fiscal year. Early adoption is permitted. The Company is a SRC for fiscal year 20 21 . For the Company this standard is effective for fiscal years beginning after December 15, 2022, and interim periods within that fiscal year. The adoption of this standard is not expected to have a material impact on the Company’s financial statements and related disclosures .

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Schedule of Financial Assets Measured and Recognized at Fair Value	As of March 31, 2022, financial assets measured and recognized at fair value were as follows (in thousands): Fair Value Measurements at March 31, 2022 Level 1 Level 2 Level 3 Total Assets U.S. government bonds $ 6,610 $ — $ — $ 6,610 Foreign government agency bonds (1) — 6,507 — 6,507 Corporate bonds — 31,034 — 31,034 Asset backed securities — 15,087 — 15,087 Marketable securities 6,610 52,628 — 59,238 Money market funds (2) 21,334 — — 21,334 Total fair value of assets $ 27,944 $ 52,628 $ — $ 80,572 (1) Consists of short-term agency bonds of Asian Development Bank and International Bank for Reconstruction and Development. (2) Included in cash and cash equivalents on the balance sheet. Fair Value Measurements at March 31, 2022 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimate Fair Value Assets U.S. government bonds $ 6,640 $ — $ (30 ) $ 6,610 Foreign government agency bonds (1) 6,513 — (6 ) 6,507 Corporate bonds 31,085 — (51 ) 31,034 Asset backed securities 15,121 — (34 ) 15,087 Marketable securities 59,359 — (121 ) 59,238 Money market funds (2) 21,334 — — 21,334 Total fair value of assets $ 80,693 $ — $ (121 ) $ 80,572 (1) Consists of short-term agency bonds of Asian Development Bank and International Bank for Reconstruction and Development. (2) Included in cash and cash equivalents on the balance sheet. As of December 31, 2021, financial assets measured and recognized at fair value were as follows (in thousands): Fair Value Measurements at December 31, 2021 Level 1 Level 2 Level 3 Total Assets U.S. government bonds $ 4,667 $ — $ — $ 4,667 Foreign government agency bonds (1) — 6,526 — 6,526 Corporate bonds — 49,989 — 49,989 Asset backed securities — 18,753 — 18,753 Marketable securities 4,667 75,268 — 79,935 Money market funds (2) 15,809 — — 15,809 Total fair value of assets $ 20,476 $ 75,268 $ — $ 95,744 (1) Consists of short-term agency bonds of Asian Development Bank and International Bank for Reconstruction and Development. (2) Included in cash and cash equivalents on the balance sheet. Fair Value Measurements at December 31, 2021 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimate Fair Value Assets U.S. government bonds $ 4,670 $ — $ (3 ) $ 4,667 Foreign government agency bonds (1) 6,530 — (4 ) 6,526 Corporate bonds 50,008 — (19 ) 49,989 Asset backed securities 18,769 — (16 ) 18,753 Marketable securities 79,977 — (42 ) 79,935 Money market funds (2) 15,809 — — 15,809 Total fair value of assets $ 95,786 $ — $ (42 ) $ 95,744 (1) Consists of short-term agency bonds of Asian Development Bank and International Bank for Reconstruction and Development. (2) Included in cash and cash equivalents on the balance sheet.

Balance Sheet Components (Table

Balance Sheet Components (Tables)	3 Months Ended
	Mar. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Schedule of Accrued and Other Current Liabilities	Accrued and other current liabilities consisted of the following (in thousands): March 31, December 31, 2022 2021 Accrued salaries and benefits $ 919 $ 2,117 Accrued research and development expenses 2,728 3,396 Accrued professional services 364 361 Other 56 69 Total $ 4,067 $ 5,943

Long-Term Debt (Tables)

Long-Term Debt (Tables)	3 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Summary of Future Contractual Maturities of Debt	As of March 31, 2021, the future contractual maturities of debt by fiscal year are as follows (in thousands): 2022 (remaining nine months) $ 333 Total future maturities of debt $ 333

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2022
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Stock Option Activity	A summary of stock option activity for the three months ended March 31, 2022 is set forth below: Outstanding Options Shares Available for Grant Number of Shares Weighted Average Exercise Price Weighted- Average Remaining Contractual Term (Years) Balance, January 1, 2022 1,493,893 3,202,588 $ 9.14 7.73 Additional shares authorized 1,261,822 Options granted (63,000 ) 63,000 $ 4.36 9.88 Options cancelled 50,685 (50,685 ) $ 9.28 Balance, March 31, 2022 2,743,400 3,214,903 $ 9.04 7.65 Exercisable as of March 31, 2022 1,784,053 $ 8.46 7.09 Vested and expected to vest, March 31, 2022 3,214,903 $ 9.04 7.65
Summary of Stock Based Compensation Expense	Total stock-based compensation expense recorded related to options granted to employees and non-employees was as follows (in thousands): Three Months March 31, 2022 2021 Research and development $ 436 $ 444 General and administrative 803 1,025 $ 1,239 $ 1,469

Net Loss Per Share Attributab_2

Net Loss Per Share Attributable to Common Stockholders (Tables)	3 Months Ended
	Mar. 31, 2022
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders	The following table sets forth the computation of basic and diluted net loss per share attributable to common stockholders (in thousands, except share and per share data): Three Months Ended March 31, 2022 2021 Numerator: Net loss attributable to common stockholders $ (15,517 ) $ (10,457 ) Denominator: Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted 31,545,564 21,975,407 Net loss per share attributable to common stockholders, basic and diluted $ (0.49 ) $ (0.48 )
Schedule of Potentially Dilutive Securities Excluded from Computation of Diluted Net Loss Per Share	The following outstanding shares of potentially dilutive securities were excluded from the computation of diluted net loss per share attributable to common stockholders for the period presented because including them would have been antidilutive: March 31, 2022 2021 Options to purchase common stock 3,214,903 3,157,527 Shares committed under ESPP 28,746 — Total 3,243,649 3,157,527

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Mar. 31, 2022
Commitments And Contingencies Disclosure [Abstract]
Schedule of Operating Lease Cost	Operating lease cost consists of the following (in thousands): Three Months Ended March 31, 2022 Operating lease cost $ 39 Short-term lease cost 33 Total lease cost $ 72
Schedule of Future Minimum Lease Payments Under Non-cancelable Operating Leases	Future minimum lease payments under non-cancelable operating leases as of December 31, 2021 were as follows (in thousands): Operating Leases 2022 $ 201 Total minimum lease payments $ 201 The maturities of operating lease liabilities as of March 31, 2022 are as follows (in thousands): March 31, 2022 2022 (remaining nine months) $ 106 2023 141 Total undiscounted lease payments 247 Less: imputed interest 7 Total operating lease liability 240 Less: current portion 136 Operating lease liability, net of current portion $ 104

Organization and Summary of S_3

Organization and Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	Feb. 26, 2021	Mar. 31, 2021	Mar. 31, 2021	Mar. 31, 2022	Jan. 01, 2022	Dec. 31, 2021
Organization And Summary Of Significant Accounting Policies [Line Items]
Proceeds from private placement financing, net of issuance costs			$ 75,215
Accumulated deficit				$ 157,253		$ 141,736
Cash, cash equivalents and marketable securities				80,600
Operating lease right-of-use asset				244
Operating lease, liability				$ 240
ASU 2016-02
Organization And Summary Of Significant Accounting Policies [Line Items]
Change in accounting principle, ASU, adopted [true false]				true
Change in accounting principle, ASU, adoption date				Jan. 1, 2022
Change in accounting principle, ASU, immaterial effect [true false]				true
Operating lease right-of-use asset					$ 100
Operating lease, liability					$ 100
Securities Purchase Agreement
Organization And Summary Of Significant Accounting Policies [Line Items]
Gross proceeds from issuance of common stock	$ 80,000
Common Stock
Organization And Summary Of Significant Accounting Policies [Line Items]
Share issued			14,084,507
Common Stock | Securities Purchase Agreement
Organization And Summary Of Significant Accounting Policies [Line Items]
Share issued	14,084,507
Shares issued, price per share	$ 5.68
Proceeds from private placement financing, net of issuance costs		$ 75,200

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Financial Assets Measured and Recognized at Fair Value (Details) - Recurring - USD ($) $ in Thousands		Mar. 31, 2022	Dec. 31, 2021
Assets
Marketable Securities		$ 59,238	$ 79,935
Total fair value of assets		80,572	95,744
Marketable Securities Amortized Cost		59,359	79,977
Marketable Securities Gross Unrealized Losses		(121)	(42)
Marketable Securities Estimate Fair Value		59,238	79,935
Amortized Cost		80,693	95,786
Gross Unrealized Losses		(121)	(42)
Estimate Fair Value		80,572	95,744
U.S. government Bonds
Assets
Marketable Securities		6,610	4,667
Marketable Securities Amortized Cost		6,640	4,670
Marketable Securities Gross Unrealized Losses		(30)	(3)
Marketable Securities Estimate Fair Value		6,610	4,667
Foreign Government Agency Bonds
Assets
Marketable Securities	[1]	6,507	6,526
Marketable Securities Amortized Cost	[1]	6,513	6,530
Marketable Securities Gross Unrealized Losses	[1]	(6)	(4)
Marketable Securities Estimate Fair Value	[1]	6,507	6,526
Corporate Bonds
Assets
Marketable Securities		31,034	49,989
Marketable Securities Amortized Cost		31,085	50,008
Marketable Securities Gross Unrealized Losses		(51)	(19)
Marketable Securities Estimate Fair Value		31,034	49,989
Asset Backed Securities
Assets
Marketable Securities		15,087	18,753
Marketable Securities Amortized Cost		15,121	18,769
Marketable Securities Gross Unrealized Losses		(34)	(16)
Marketable Securities Estimate Fair Value		15,087	18,753
Money Market Funds
Assets
Money market funds	[2]	21,334	15,809
Amortized Cost	[2]	21,334	15,809
Estimate Fair Value	[2]	21,334	15,809
Level 1
Assets
Marketable Securities		6,610	4,667
Total fair value of assets		27,944	20,476
Level 1 | U.S. government Bonds
Assets
Marketable Securities		6,610	4,667
Level 1 | Money Market Funds
Assets
Money market funds	[2]	21,334	15,809
Level 2
Assets
Marketable Securities		52,628	75,268
Total fair value of assets		52,628	75,268
Level 2 | Foreign Government Agency Bonds
Assets
Marketable Securities	[1]	6,507	6,526
Level 2 | Corporate Bonds
Assets
Marketable Securities		31,034	49,989
Level 2 | Asset Backed Securities
Assets
Marketable Securities		$ 15,087	$ 18,753
[1]	Consists of short-term agency bonds of Asian Development Bank and International Bank for Reconstruction and Development.
[2]	Included in cash and cash equivalents on the balance sheet.

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	Mar. 31, 2022	Dec. 31, 2021
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial liabilities measured and recognized	$ 0	$ 0

Balance Sheet Components - Addi

Balance Sheet Components - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Property Plant And Equipment [Abstract]
Depreciation expense	$ 92	$ 80
Accumulated depreciation	$ 700		$ 600

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Payables And Accruals [Abstract]
Accrued salaries and benefits	$ 919	$ 2,117
Accrued research and development expenses	2,728	3,396
Accrued professional services	364	361
Other	56	69
Total	$ 4,067	$ 5,943

Long-Term Debt - Additional Inf

Long-Term Debt - Additional Information (Details) - USD ($)	Oct. 26, 2018	Mar. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Long-term debt net of debt discount and issuance costs		$ 583,000	$ 1,080,000
Loan Agreement | Silicon Valley Bank
Debt Instrument [Line Items]
Debt instrument, maximum borrowing capacity	$ 10,000,000
Debt instrument, floating interest rate percentage	6.50%
Debt instrument, interest rate increase percentage	5.00%
Debt instrument, maturity date	May 1, 2022
Long-term debt net of debt discount and issuance costs		600,000
Accrued liabilities related to accretion of final payment		$ 200,000	$ 200,000
Loan Agreement | Silicon Valley Bank | Greater above Prime Rate
Debt Instrument [Line Items]
Debt instrument, floating interest rate percentage	1.50%
Loan Agreement | Silicon Valley Bank | Term A Loan
Debt Instrument [Line Items]
Debt instrument, current borrowing capacity	$ 5,000,000
Loan Agreement | Silicon Valley Bank | Term Loan
Debt Instrument [Line Items]
Debt instrument, remaining borrowing capacity, no longer available for draw	$ 5,000,000

Long-Term Debt - Summary of Fut

Long-Term Debt - Summary of Future Contractual Maturities of Debt (Details) $ in Thousands	Mar. 31, 2021USD ($)
Debt Disclosure [Abstract]
2022 (remaining nine months)	$ 333
Total future maturities of debt	$ 333

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Stock Option Activity (Details) - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Compensation Related Costs [Abstract]
Shares Available for Grant, Beginning Balance	1,493,893
Shares Available for Grant, Additional shares authorized	1,261,822
Shares Available for Grant, Options granted	(63,000)
Shares Available for Grant, Options cancelled	50,685
Shares Available for Grant, Ending Balance	2,743,400	1,493,893
Outstanding Options, Number of Shares, Beginning Balance	3,202,588
Outstanding Options, Number of Shares, Options granted	63,000
Outstanding Options, Number of Shares, Options cancelled	(50,685)
Outstanding Options, Number of Shares, Ending Balance	3,214,903	3,202,588
Outstanding Options, Number of Shares, Exercisable as of March 31, 2022	1,784,053
Outstanding Options, Number of Shares, Vested and expected to vest, March 31, 2022	3,214,903
Outstanding Options, Weighted Average Exercise Price, Beginning Balance	$ 9.14
Outstanding Options, Weighted Average Exercise Price, Options granted	4.36
Outstanding Options, Weighted Average Exercise Price, Options cancelled	9.28
Outstanding Options, Weighted Average Exercise Price, Ending Balance	9.04	$ 9.14
Shares Available for Grant, Exercisable as of March 31, 2022	8.46
Shares Available for Grant, Vested and expected to vest, March 31, 2022	$ 9.04
Weighted Average Remaining Contractual Term, Balance	7 years 7 months 24 days	7 years 8 months 23 days
Weighted Average Remaining Contractual Term, Options granted	9 years 10 months 17 days
Weighted Average Remaining Contractual Term, Exercisable as of March 31, 2022	7 years 1 month 2 days
Weighted Average Remaining Contractual Term, Vested and expected to vest, March 31, 2022	7 years 7 months 24 days

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average grant-date fair value of options granted	$ 3.42	$ 4.16
Unrecognized stock-based compensation expense	$ 8.6
Unrecognized stock-based compensation expense, weighted-average recognition period	2 years
Fair value of options vested	$ 1.2	$ 2.9
2019 Employee Share Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares reserved for issuance	792,731

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 1,239	$ 1,469
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	436	444
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 803	$ 1,025

Net Loss Per Share Attributab_3

Net Loss Per Share Attributable to Common Stockholders - Schedule of Computation of Basic and Diluted Net Loss Per Share Attributable to Common Stockholders (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Numerator:
Net loss attributable to common stockholders	$ (15,517)	$ (10,457)
Denominator:
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted	31,545,564	21,975,407
Net loss per share attributable to common stockholders, basic and diluted	$ (0.49)	$ (0.48)

Net Loss Per Share Attributab_4

Net Loss Per Share Attributable to Common Stockholders - Schedule of Potentially Dilutive Securities Excluded from Computation of Diluted Net Loss Per Share (Details) - shares	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities outstanding	3,243,649	3,157,527
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities outstanding	3,214,903	3,157,527
Shares Committed Under E S P P Member
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities outstanding	28,746

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022USD ($)Stockholdershares	Mar. 31, 2021USD ($)
Related Party Transaction [Line Items]
Issuance of common stock, net of issuance costs		$ 75,215
Two Existing Stockholders Affiliated with Directors
Related Party Transaction [Line Items]
Number of existing stockholders of company affiliated directors purchased common stock | Stockholder	2
Share issued | shares	2,464,788
Issuance of common stock, net of issuance costs	$ 14,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Lease Liabilities Payments Due [Abstract]
Operating lease, expense		$ 0.1
Operating lease remaining term	1 year 3 months 18 days
Operating lease discount rate	4.90%
Cash paid included in operating lease liabilities	$ 0.1

Commitments and Contingencies_2

Commitments and Contingencies - Schedule of Operating Lease Cost (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2022USD ($)
Commitments And Contingencies Disclosure [Abstract]
Operating lease cost	$ 39
Short-term lease cost	33
Total lease cost	$ 72

Commitments and Contingencies_3

Commitments and Contingencies - Schedule of Future Minimum Lease Payments Under Non-cancelable Operating Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Operating Lease Liabilities Payments Due [Abstract]
2022	$ 106	$ 201
Total minimum lease payments	$ 247	$ 201

Commitments and Contingencies_4

Commitments and Contingencies - Schedule of Maturities of Operating Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Commitments And Contingencies Disclosure [Abstract]
2022	$ 106	$ 201
2023	141
Total minimum lease payments	247	$ 201
Less: imputed interest	7
Total operating lease liability	240
Operating lease liability	136
Operating lease liability, net of current portion	$ 104

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Tax Disclosure [Abstract]
Income tax provision	$ 0	$ 0