Satsuma Pharmaceuticals (STSA) 10-Q 10 Aug 21 2021 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2021	Aug. 06, 2021
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q2
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		31,529,417

Condensed Balance Sheets (Unaud

Condensed Balance Sheets (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Assets
Cash and cash equivalents	$ 53,862	$ 36,326
Short-term marketable securities	67,302	31,910
Prepaid expenses and other current assets	5,062	5,550
Total current assets	126,226	73,786
Property and equipment, net	7,130	6,473
Other non-current assets	1,963	774
Total assets	135,319	81,033
Liabilities
Accounts payable	3,107	3,381
Accrued and other current liabilities	2,406	2,675
Current portion of long-term debt	2,062	1,990
Total current liabilities	7,575	8,046
Long-term debt		1,042
Other noncurrent liabilities	5	9
Total liabilities	7,580	9,097
Commitments and contingencies (Note 8)
Stockholders’ equity
Preferred stock, $0.0001 par value, 10,000,000 shares authorized as of June 30, 2021 and December 31, 2020; no shares issued and outstanding as of June 30, 2021 and December 31, 2020
Common stock, $0.0001 par value, 300,000,000 shares authorized as of June 30, 2021 and December 31, 2020, respectively; 31,529,417 shares and 17,436,978 shares issued and outstanding as of June 30, 2021 and December 31, 2020	3	2
Additional paid-in-capital	240,594	162,469
Accumulated other comprehensive income	(5)	29
Accumulated deficit	(112,853)	(90,564)
Total stockholders’ equity	127,739	71,936
Total liabilities and stockholders’ equity	$ 135,319	$ 81,033

Condensed Balance Sheets (Una_2

Condensed Balance Sheets (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2021	Dec. 31, 2020
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	31,529,417	17,436,978
Common stock, shares outstanding	31,529,417	17,436,978

Condensed Statements of Operati

Condensed Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Operating expenses
Research and development	$ 8,443	$ 8,829	$ 15,599	$ 18,477
General and administrative	3,383	2,671	6,677	5,194
Total operating expenses	11,826	11,500	22,276	23,671
Loss from operations	(11,826)	(11,500)	(22,276)	(23,671)
Interest income	41	325	91	827
Interest expense	(47)	(94)	(104)	(198)
Net loss	(11,832)	(11,269)	(22,289)	(23,042)
Unrealized (loss) gain on marketable securities	(8)	250	(34)	218
Comprehensive loss	$ (11,840)	$ (11,019)	$ (22,323)	$ (22,824)
Net loss per share attributable to common stockholders, basic and diluted	$ (0.38)	$ (0.65)	$ (0.83)	$ (1.33)
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted	31,529,417	17,394,466	26,778,804	17,388,741

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, 2019	$ 115,335	$ 2	$ 158,317	$ 17	$ (43,001)
Beginning balance, Shares at Dec. 31, 2019		17,382,047
Issuance of common stock upon exercise of stock options	11		11
Issuance of common stock upon exercise of stock options, Shares		4,200
Stock-based compensation	449		449
Net loss	(11,773)				(11,773)
Other comprehensive income (loss)	(32)			(32)
Ending balance at Mar. 31, 2020	103,990	$ 2	158,777	(15)	(54,774)
Ending Balance, Shares at Mar. 31, 2020		17,386,247
Beginning balance at Dec. 31, 2019	115,335	$ 2	158,317	17	(43,001)
Beginning balance, Shares at Dec. 31, 2019		17,382,047
Net loss	(23,042)
Ending balance at Jun. 30, 2020	93,934	$ 2	159,740	235	(66,043)
Ending Balance, Shares at Jun. 30, 2020		17,404,962
Beginning balance at Dec. 31, 2019	115,335	$ 2	158,317	17	(43,001)
Beginning balance, Shares at Dec. 31, 2019		17,382,047
Ending balance at Dec. 31, 2020	71,936	$ 2	162,469	29	(90,564)
Ending Balance, Shares at Dec. 31, 2020		17,436,978
Beginning balance at Mar. 31, 2020	103,990	$ 2	158,777	(15)	(54,774)
Beginning balance, Shares at Mar. 31, 2020		17,386,247
Issuance of common stock upon exercise of stock options	39		39
Issuance of common stock upon exercise of stock options, Shares		18,715
Stock-based compensation	924		924
Net loss	(11,269)				(11,269)
Other comprehensive income (loss)	250			250
Ending balance at Jun. 30, 2020	93,934	$ 2	159,740	235	(66,043)
Ending Balance, Shares at Jun. 30, 2020		17,404,962
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	75,215	$ 1	75,214
Issuance of common stock in private placement financing, net of issuance costs, 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, 2020	71,936	$ 2	162,469	29	(90,564)
Beginning balance, Shares at Dec. 31, 2020		17,436,978
Net loss	(22,289)
Ending balance at Jun. 30, 2021	127,739	$ 3	240,594	(5)	(112,853)
Ending Balance, Shares at Jun. 30, 2021		31,529,417
Beginning balance at Mar. 31, 2021	138,145	$ 3	239,160	3	(101,021)
Beginning balance, Shares at Mar. 31, 2021		31,529,417
Stock-based compensation	1,434		1,434
Net loss	(11,832)				(11,832)
Other comprehensive income (loss)	(8)			(8)
Ending balance at Jun. 30, 2021	$ 127,739	$ 3	$ 240,594	$ (5)	$ (112,853)
Ending Balance, Shares at Jun. 30, 2021		31,529,417

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	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Cash flows from operating activities
Net loss	$ (22,289)	$ (23,042)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation	185	106
Non-cash interest expense, and amortization of debt discount and issuance costs	30	58
Net amortization of premiums and accretion of discounts on marketable securities	169	(32)
Stock-based compensation	2,903	1,373
Changes in assets and liabilities
Prepaid expenses and other assets	(701)	(61)
Accounts payable	394	(1,776)
Accrued and other current liabilities	(269)	368
Other non-current liabilities	(4)	(6)
Net cash used in operating activities	(19,582)	(23,012)
Cash flows from investing activities
Purchases of marketable securities	(53,895)	(12,222)
Proceeds from maturities of marketable securities	18,300	46,049
Purchases of property and equipment	(1,510)	(487)
Net cash (used in) provided by investing activities	(37,105)	33,340
Cash flows from financing activities
Repayment of debt	(1,000)	(1,000)
Proceeds from private placement financing, net of issuance costs	75,215
Proceeds from exercise of common stock options	8	50
Net cash provided by (used in) financing activities	74,223	(950)
Net increase in cash and cash equivalents	17,536	9,378
Cash and cash equivalents
Cash and cash equivalents, at beginning of period	36,326	22,755
Cash and cash equivalents, at end of period	53,862	32,133
Supplemental disclosure of cash flow information:
Cash paid for income taxes	5
Cash paid for interest	79	152
Supplemental non-cash investing and financing activities:
Purchases of property and equipment in accounts payable and accrued and other current liabilities	$ 56	$ 105

Organization and Summary of Sig

Organization and Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2021
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 $112.9 million as of June 30, 2021. 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, raise additional capital or reduce certain discretionary spending would have a material adverse effect on the Company’s ability to achieve its intended business objectives. As of June 30, 2021, the Company had cash, cash equivalents and marketable securities of $121.2 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 and six months ended June 30, 2021. 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”). Unaudited Interim Financial Information The accompanying condensed balance sheet as of June 30, 2021, the condensed statements of operations and comprehensive loss, the condensed statements of stockholders’ equity for the three and six months ended June 30, 2021 and 2020 and the condensed statements of cash flows for the six months ended June 30, 2021 and 2020 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 June 30, 2021 and the results of its operations for the three and six months ended June 30, 2021 and 2020 and its cash flows for the six months ended June 30, 2021 and 2020. The financial data and other information disclosed in these notes related to the three and six months ended June 30, 2021 and 2020 are also unaudited. The results for the three and six months ended June 30, 2021 are not necessarily indicative of results to be expected for the year ending December 31, 20 2 1 , any other interim periods, or any future year or period. The balance sheet as of December 31, 20 20 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, 2020, which are included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020 filed with the Securities and Exchange Commission, or the SEC, on March 25, 2021. 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 short-term 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. Fair Value of Financial Instruments The carrying amounts of certain of the Company’s financial instruments, including cash equivalents, accounts payable and accrued liabilities, approximate fair value due to their relatively short maturities and market interest rates, if applicable. Refer to Note 2 for details on the fair value of marketable securities. Property and Equipment, Net Property and equipment are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, which generally ranges from three to five years. Leasehold improvements are stated at cost and amortized over the shorter of the useful lives of the assets or the lease term. Maintenance and repairs are charged to expense as incurred. When assets are retired or otherwise disposed of, the cost and accumulated depreciation are removed from the condensed condensed June 30 Net Loss per Share Attributable to Common Stockholders Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common stock outstanding during the period, without consideration of potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common stock and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, stock options and warrants to purchase common stock are considered to be potentially dilutive securities. Basic and diluted net loss per share attributable to common stockholders are presented in conformity with the two-class method required for participating securities as the convertible preferred stock is considered a participating security because it participates in dividends with common stock. The holders of convertible preferred stock do not have a contractual obligation to share in the Company’s losses. As such, the net loss was attributed entirely to common stockholders. Because the Company has reported a net loss for all periods presented, diluted net loss per common share is the same as basic net loss per common share for those periods. Income Taxes On March 18, 2020, the Families First Coronavirus Response Act (“FFCR Act”), and on March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) were each enacted in response to the COVID-19 pandemic. The FFCR Act and the CARES Act contain numerous tax-related provisions relating to refundable payroll tax credits, deferment of employer side social security payments, net operating loss carryback periods, alternative minimum tax credit refunds, modifications to the net interest deduction limitations and technical corrections to tax depreciation methods for qualified improvement property. On June 29, 2020, California State Assembly Bill 85 (the “Trailer Bill”) was enacted which suspends the use of California net operating loss (“NOL”) deductions and certain tax credits, including research and development tax credits, for the 2020, 2021, and 2022 tax years. The FFCR Act, CARES Act and Trailer Bill did not have a material impact on the Company’s unaudited interim condensed financial statements as of June 30, 2021; however, the Company continues to examine the impacts the FFCR Act and CARES Act may have on its business, results of operations, financial condition and liquidity. Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) under its accounting standard codifications (“ASC”) or other standard setting bodies and adopted by the Company as of the specified effective date, unless otherwise discussed below. Recently Adopted Accounting Pronouncements In December 2019, the FASB issued ASU 2019-12 Income Taxes (Topic 740) Simplifying the Accounting for Income Taxes. ASU 2019-12 New Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326) 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	6 Months Ended
	Jun. 30, 2021
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 June 30, 2021, financial assets measured and recognized at fair value were as follows (in thousands): Fair Value Measurements at June 30, 2021 Quoted Price in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets Foreign government agency bonds (1) $ — $ 4,015 $ — $ 4,015 Corporate bonds — 51,027 — 51,027 Asset backed securities — 12,260 — 12,260 Marketable securities — 67,302 — 67,302 Money market funds (2) 53,836 — — 53,836 Total fair value of assets $ 53,836 $ 67,302 $ — $ 121,138 (1) Consists of short-term agency bonds of Asian Development Bank. (2) Included in cash and cash equivalents on the balance sheet. Fair Value Measurements at June 30, 2021 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimate Fair Value Assets Foreign government agency bonds (1) $ 4,015 $ — $ — $ 4,015 Corporate bonds 51,027 — — 51,027 Asset backed securities 12,265 — (5 ) 12,260 Marketable securities 67,307 — (5 ) 67,302 Money market funds ( 2 ) 53,836 — — 53,836 Total fair value of assets $ 121,143 $ — $ (5 ) $ 121,138 (1) Consists of short-term agency bonds of Asian Development Bank. (2) Included in cash and cash equivalents on the balance sheet As of December 31, 2020, financial assets measured and recognized at fair value were as follows (in thousands): Fair Value Measurements at December 31, 2020 Quoted Price in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets Corporate bonds $ — $ 31,910 $ — $ 31,910 Marketable securities — 31,910 — 31,910 Money market funds (1) 36,304 — — 36,304 Total fair value of assets $ 36,304 $ 31,910 $ — $ 68,214 (1) Included in cash and cash equivalents on the balance sheet. Fair Value Measurements at December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimate Fair Value Assets Corporate bonds $ 31,881 $ 30 $ (1 ) $ 31,910 Marketable securities 31,881 30 (1 ) 31,910 Money market funds (1) 36,304 — — 36,304 Total fair value of assets $ 68,185 $ 30 $ (1 ) $ 68,214 (1) Included in cash and cash equivalents on the balance sheet. There were no financial liabilities measured and recognized at fair value as of June 30, 2021 and December 31, 2020. As of June 30, 2021, the fair value of the Term Loan approximates the carrying amount of the loan as the Term Loan bears floating interest rate that approximates the market rate.

Accrued and Other Current Liabi

Accrued and Other Current Liabilities	6 Months Ended
	Jun. 30, 2021
Payables And Accruals [Abstract]
Accrued and Other Current Liabilities	3. Accrued and Other Current Liabilities Accrued and other current liabilities consisted of the following (in thousands): June 30, December 31, 2021 2020 Accrued salaries and benefits $ 1,056 $ 1,330 Accrued research and development expenses 970 910 Accrued professional services 279 232 Accrued interest 10 16 Other 91 187 Total $ 2,406 $ 2,675

Long-Term Debt

Long-Term Debt	6 Months Ended
	Jun. 30, 2021
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 (the “Term B Loan” and together with the Term A Loan, the “Term Loans”) is available for draw down by the Company in $1.0 million increments. 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 June 30, 2021, the future contractual maturities of debt by fiscal year are as follows (in thousands): 2021 (remaining six months) $ 1,000 2022 833 Total future maturities of debt $ 1,833 As of June 30, 2021, the term loan advances, net of debt discount and debt issuance costs, were $2.1 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 December 31, 2020 and $0.2 million as of June 30, 2021 and were included in long-term debt and the current portion of long-term debt on the Company’s condensed balance sheets, respectively.

Stock-Based Compensation

Stock-Based Compensation	6 Months Ended
	Jun. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Stock-Based Compensation	5 . Stock-Based Compensation 2019 Incentive Award Plan The Company’s Board of Directors adopted and the Company’s stockholders approved, effective on the day of effectiveness of the registration statement on Form S-1, the 2019 Incentive Award Plan (the “2019 Plan”). Awards granted under the 2019 Plan may be either incentive stock options (“ISOs”), nonqualified stock options (“NSOs”), stock appreciation rights (“SARs”), or restricted stock units (“RSUs”). ISOs may be granted only to Company employees (including officers and directors who are also employees). 2016 Incentive Award Plan In 2016, the Company established its 2016 Equity Incentive Plan (the “2016 Plan”) which provides for the granting of stock options to employees and consultants of the Company. Awards granted under the 2016 Plan may be either incentive stock options (“ISOs”), nonqualified stock options (“NSOs”), stock appreciation rights (“SARs”), or restricted stock units (“RSUs”). ISOs may be granted only to Company employees (including officers and directors who are also employees). NSOs may be granted to Company employees and consultants. The exercise price of ISOs and NSOs shall not be less than 100% of the estimated fair value of the shares on the date of grant. The exercise price of ISOs granted to an employee who, at the time of grant, owns stock representing more than 10% (“10% stockholder”) of the voting power of all classes of stock of the Company shall be no less than 110% of the estimated fair value of the shares on the date of grant. The options usually have a term of 10 years (or no more than five years if granted to a 10% stockholder). Vesting conditions determined by the plan administrator may apply to stock options and may include continued service, performance and/or other conditions. Generally, options and restricted stock awards vest over a four-year In January 2021, the number of shares of common stock available for issuance under the 2019 Plan was increased by 697,479 shares as a result of the automatic increase provision in the 2019 Plan. Activity under the 2019 Plan and 2016 Plan 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, 2021 844,475 3,162,459 $ 9.31 8.79 Additional shares authorized 697,479 Options granted (36,000 ) 36,000 $ 5.01 9.90 Options exercised — (7,932 ) $ 1.04 Balance, June 30, 2021 1,505,954 3,190,527 $ 9.28 8.31 Exercisable as of June 30, 2021 1,259,176 $ 7.84 7.44 Vested and expected to vest, June 30, 2021 3,190,527 $ 9.28 8.31 The weighted-average grant-date fair value of options granted during the six months ended June 30, 2021 and 2020 was $3.85 and $17.33 per share, respectively. As of June 30, 2021, the total unrecognized stock-based compensation expense for stock options was $12.1 million, which is expected to be recognized over a weighted-average period of 2.6 years. The total fair value of options vested for the six months ended June 30, 2021 and 2020 was $4.9 million and $0.5 million, respectively. Fair Value of Common Stock Prior to the IPO, the fair value of the Company’s common stock underlying the stock options was determined by the Board of Directors with assistance from management and, in part, on input from an independent third-party valuation firm. The Board of Directors determined the fair value of common stock by considering a number of objective and subjective factors, including valuations of comparable companies, sales of convertible preferred stock, operating and financial performance, the lack of liquidity of the Company’s common stock and the general and industry-specific economic outlook. Subsequent to the Company’s IPO, the fair value of the Company’s common stock is determined based on its closing market price. 2019 Share Purchase Plan In September 2019, the Company adopted the 2019 Employee Share Purchase Plan (“ESPP”), which became effective on the business day prior to the effectiveness of the registration statement relating to the IPO . A total of 160,000 shares of common stock were initially reserved for issuance under the ESPP. In January 2021, the number of shares of common stock available for issuance under the ESPP was increased by 174,369 shares as a result of the automatic increase provision in the ESPP. The first offering period was for 6.5 months beginning from May 1, 2020 until November 15, 2020. The Company issued 14,766 shares under the ESPP for the year ended December 31, 2020. As of June 30, 2021, 493,423 shares under the ESPP remain available for purchase. The offering period and purchase period is determined by the board of directors. A new offering period running 5.5 months has been authorized beginning July 1, 2021 through December 15, 2021. 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 Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Research and development $ 452 $ 331 $ 896 $ 516 General and administrative 982 593 2,007 857 $ 1,434 $ 924 $ 2,903 $ 1,373

Net Loss Per Share Attributable

Net Loss Per Share Attributable to Common Stockholders	6 Months Ended
	Jun. 30, 2021
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 June 30, Six Months Ended June 30, 2021 2020 2021 2020 Numerator: Net loss attributable to common stockholders $ (11,832 ) $ (11,269 ) $ (22,289 ) $ (23,042 ) Denominator: Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted 31,529,417 17,394,466 26,778,804 17,388,741 Net loss per share attributable to common stockholders, basic and diluted $ (0.38 ) $ (0.65 ) $ (0.83 ) $ (1.33 ) 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: June 30, 2021 2020 Options to purchase common stock 3,190,527 2,190,659 Warrants to purchase common stock — 5,116 Total 3,190,527 2,195,775

Related Party Transaction

Related Party Transaction	6 Months Ended
	Jun. 30, 2021
Related Party Transactions [Abstract]
Related Party Transactions	7 . Related Party Transactions In March 2021, two existing stockholders of the Company affiliated 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.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2021
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	8 . Commitments and Contingencies Operating Leases Future minimum lease payments under non-cancelable operating leases as of June 30, 2021 were as follows (in thousands): Operating Leases 2021 (remaining six months) $ 121 2022 93 Total minimum lease payments $ 214

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2021
Income Tax Disclosure [Abstract]
Income Taxes	9 . Income Taxes For the six months ended June 30, 2021 and 2020, 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	6 Months Ended
	Jun. 30, 2021
Subsequent Events [Abstract]
Subsequent Events	1 0 . Subsequent Events For the purposes of the unaudited interim condensed financial statements as of June 30, 2021 and for the three and six months ended, the Company has evaluated the subsequent events through August 10, 2021, the date the unaudited interim condensed financial statements were issued.

Organization and Summary of S_2

Organization and Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2021
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 $112.9 million as of June 30, 2021. 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, raise additional capital or reduce certain discretionary spending would have a material adverse effect on the Company’s ability to achieve its intended business objectives. As of June 30, 2021, the Company had cash, cash equivalents and marketable securities of $121.2 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 and six months ended June 30, 2021.
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”).
Unaudited Interim Financial Information	Unaudited Interim Financial Information The accompanying condensed balance sheet as of June 30, 2021, the condensed statements of operations and comprehensive loss, the condensed statements of stockholders’ equity for the three and six months ended June 30, 2021 and 2020 and the condensed statements of cash flows for the six months ended June 30, 2021 and 2020 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 June 30, 2021 and the results of its operations for the three and six months ended June 30, 2021 and 2020 and its cash flows for the six months ended June 30, 2021 and 2020. The financial data and other information disclosed in these notes related to the three and six months ended June 30, 2021 and 2020 are also unaudited. The results for the three and six months ended June 30, 2021 are not necessarily indicative of results to be expected for the year ending December 31, 20 2 1 , any other interim periods, or any future year or period. The balance sheet as of December 31, 20 20 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, 2020, which are included in the Company’s Annual Report on Form 10-K for the fiscal year ended December 31, 2020 filed with the Securities and Exchange Commission, or the SEC, on March 25, 2021.
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 short-term 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.
Fair Value of Financial Instruments	Fair Value of Financial Instruments The carrying amounts of certain of the Company’s financial instruments, including cash equivalents, accounts payable and accrued liabilities, approximate fair value due to their relatively short maturities and market interest rates, if applicable. Refer to Note 2 for details on the fair value of marketable securities.
Property and Equipment, Net	Property and Equipment, Net Property and equipment are stated at cost less accumulated depreciation. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, which generally ranges from three to five years. Leasehold improvements are stated at cost and amortized over the shorter of the useful lives of the assets or the lease term. Maintenance and repairs are charged to expense as incurred. When assets are retired or otherwise disposed of, the cost and accumulated depreciation are removed from the condensed condensed June 30
Net Loss per Share Attributable to Common Stockholders	Net Loss per Share Attributable to Common Stockholders Basic net loss per common share is calculated by dividing the net loss attributable to common stockholders by the weighted-average number of common stock outstanding during the period, without consideration of potentially dilutive securities. Diluted net loss per share is computed by dividing the net loss attributable to common stockholders by the weighted-average number of common stock and potentially dilutive securities outstanding for the period. For purposes of the diluted net loss per share calculation, stock options and warrants to purchase common stock are considered to be potentially dilutive securities. Basic and diluted net loss per share attributable to common stockholders are presented in conformity with the two-class method required for participating securities as the convertible preferred stock is considered a participating security because it participates in dividends with common stock. The holders of convertible preferred stock do not have a contractual obligation to share in the Company’s losses. As such, the net loss was attributed entirely to common stockholders. Because the Company has reported a net loss for all periods presented, diluted net loss per common share is the same as basic net loss per common share for those periods.
Income Taxes	Income Taxes On March 18, 2020, the Families First Coronavirus Response Act (“FFCR Act”), and on March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) were each enacted in response to the COVID-19 pandemic. The FFCR Act and the CARES Act contain numerous tax-related provisions relating to refundable payroll tax credits, deferment of employer side social security payments, net operating loss carryback periods, alternative minimum tax credit refunds, modifications to the net interest deduction limitations and technical corrections to tax depreciation methods for qualified improvement property. On June 29, 2020, California State Assembly Bill 85 (the “Trailer Bill”) was enacted which suspends the use of California net operating loss (“NOL”) deductions and certain tax credits, including research and development tax credits, for the 2020, 2021, and 2022 tax years. The FFCR Act, CARES Act and Trailer Bill did not have a material impact on the Company’s unaudited interim condensed financial statements as of June 30, 2021; however, the Company continues to examine the impacts the FFCR Act and CARES Act may have on its business, results of operations, financial condition and liquidity.
Recent Accounting Pronouncements	Recent Accounting Pronouncements From time to time, new accounting pronouncements are issued by the Financial Accounting Standards Board (“FASB”) under its accounting standard codifications (“ASC”) or other standard setting bodies and adopted by the Company as of the specified effective date, unless otherwise discussed below. Recently Adopted Accounting Pronouncements In December 2019, the FASB issued ASU 2019-12 Income Taxes (Topic 740) Simplifying the Accounting for Income Taxes. ASU 2019-12 New Accounting Pronouncements Not Yet Adopted In February 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) In June 2016, the FASB issued ASU No. 2016-13, Financial Instruments - Credit Losses (Topic 326) 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)	6 Months Ended
	Jun. 30, 2021
Fair Value Disclosures [Abstract]
Schedule of Financial Assets Measured and Recognized at Fair Value	As of June 30, 2021, financial assets measured and recognized at fair value were as follows (in thousands): Fair Value Measurements at June 30, 2021 Quoted Price in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets Foreign government agency bonds (1) $ — $ 4,015 $ — $ 4,015 Corporate bonds — 51,027 — 51,027 Asset backed securities — 12,260 — 12,260 Marketable securities — 67,302 — 67,302 Money market funds (2) 53,836 — — 53,836 Total fair value of assets $ 53,836 $ 67,302 $ — $ 121,138 (1) Consists of short-term agency bonds of Asian Development Bank. (2) Included in cash and cash equivalents on the balance sheet. Fair Value Measurements at June 30, 2021 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimate Fair Value Assets Foreign government agency bonds (1) $ 4,015 $ — $ — $ 4,015 Corporate bonds 51,027 — — 51,027 Asset backed securities 12,265 — (5 ) 12,260 Marketable securities 67,307 — (5 ) 67,302 Money market funds ( 2 ) 53,836 — — 53,836 Total fair value of assets $ 121,143 $ — $ (5 ) $ 121,138 (1) Consists of short-term agency bonds of Asian Development Bank. (2) Included in cash and cash equivalents on the balance sheet As of December 31, 2020, financial assets measured and recognized at fair value were as follows (in thousands): Fair Value Measurements at December 31, 2020 Quoted Price in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total Assets Corporate bonds $ — $ 31,910 $ — $ 31,910 Marketable securities — 31,910 — 31,910 Money market funds (1) 36,304 — — 36,304 Total fair value of assets $ 36,304 $ 31,910 $ — $ 68,214 (1) Included in cash and cash equivalents on the balance sheet. Fair Value Measurements at December 31, 2020 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Estimate Fair Value Assets Corporate bonds $ 31,881 $ 30 $ (1 ) $ 31,910 Marketable securities 31,881 30 (1 ) 31,910 Money market funds (1) 36,304 — — 36,304 Total fair value of assets $ 68,185 $ 30 $ (1 ) $ 68,214 (1) Included in cash and cash equivalents on the balance sheet.

Accrued and Other Current Lia_2

Accrued and Other Current Liabilities (Tables)	6 Months Ended
	Jun. 30, 2021
Payables And Accruals [Abstract]
Schedule of Accrued and Other Current Liabilities	Accrued and other current liabilities consisted of the following (in thousands): June 30, December 31, 2021 2020 Accrued salaries and benefits $ 1,056 $ 1,330 Accrued research and development expenses 970 910 Accrued professional services 279 232 Accrued interest 10 16 Other 91 187 Total $ 2,406 $ 2,675

Long-Term Debt (Tables)

Long-Term Debt (Tables)	6 Months Ended
	Jun. 30, 2021
Debt Disclosure [Abstract]
Summary of Future Contractual Maturities of Debt	As of June 30, 2021, the future contractual maturities of debt by fiscal year are as follows (in thousands): 2021 (remaining six months) $ 1,000 2022 833 Total future maturities of debt $ 1,833

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2021
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Schedule of Activity Under 2019 and 2016 Plan	Activity under the 2019 Plan and 2016 Plan 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, 2021 844,475 3,162,459 $ 9.31 8.79 Additional shares authorized 697,479 Options granted (36,000 ) 36,000 $ 5.01 9.90 Options exercised — (7,932 ) $ 1.04 Balance, June 30, 2021 1,505,954 3,190,527 $ 9.28 8.31 Exercisable as of June 30, 2021 1,259,176 $ 7.84 7.44 Vested and expected to vest, June 30, 2021 3,190,527 $ 9.28 8.31
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 Ended June 30, Six Months Ended June 30, 2021 2020 2021 2020 Research and development $ 452 $ 331 $ 896 $ 516 General and administrative 982 593 2,007 857 $ 1,434 $ 924 $ 2,903 $ 1,373

Net Loss Per Share Attributab_2

Net Loss Per Share Attributable to Common Stockholders (Tables)	6 Months Ended
	Jun. 30, 2021
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 June 30, Six Months Ended June 30, 2021 2020 2021 2020 Numerator: Net loss attributable to common stockholders $ (11,832 ) $ (11,269 ) $ (22,289 ) $ (23,042 ) Denominator: Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted 31,529,417 17,394,466 26,778,804 17,388,741 Net loss per share attributable to common stockholders, basic and diluted $ (0.38 ) $ (0.65 ) $ (0.83 ) $ (1.33 )
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: June 30, 2021 2020 Options to purchase common stock 3,190,527 2,190,659 Warrants to purchase common stock — 5,116 Total 3,190,527 2,195,775

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2021
Commitments And Contingencies Disclosure [Abstract]
Schedule of Future Minimum Lease Payments Under Non-cancelable Operating Leases	Future minimum lease payments under non-cancelable operating leases as of June 30, 2021 were as follows (in thousands): Operating Leases 2021 (remaining six months) $ 121 2022 93 Total minimum lease payments $ 214

Organization and Summary of S_3

Organization and Summary of Significant Accounting Policies - Additional Information (Details) - USD ($)	Feb. 26, 2021	Mar. 31, 2021	Mar. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Organization And Summary Of Significant Accounting Policies [Line Items]
Issuance of common stock in private placement financing, net of issuance costs, Shares		2,464,788
Proceeds from private placement financing, net of issuance costs				$ 75,215,000
Accumulated deficit				112,853,000	$ 90,564,000
Cash, cash equivalents and marketable securities				121,200,000
Accumulated depreciation				$ 600,000	$ 400,000
ASU 2019-12
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, 2021
Change in accounting principle, ASU, immaterial effect [true false]				true
Accounting Standards Update [Extensible List]				ASU 2019-12
Minimum
Organization And Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives of assets				3 years
Maximum
Organization And Summary Of Significant Accounting Policies [Line Items]
Estimated useful lives of assets				5 years
Securities Purchase Agreement
Organization And Summary Of Significant Accounting Policies [Line Items]
Gross proceeds from issuance of common stock	$ 80,000,000
Common Stock
Organization And Summary Of Significant Accounting Policies [Line Items]
Issuance of common stock in private placement financing, net of issuance costs, Shares			14,084,507
Common Stock | Securities Purchase Agreement
Organization And Summary Of Significant Accounting Policies [Line Items]
Issuance of common stock in private placement financing, net of issuance costs, Shares	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		Jun. 30, 2021		Dec. 31, 2020
Assets
Marketable Securities		$ 67,302		$ 31,910
Total fair value of assets		121,138		68,214
Marketable Securities Amortized Cost		67,307		31,881	[1]
Marketable Securities Gross Unrealized Gains	[1]			30
Marketable Securities Gross Unrealized Losses		(5)		(1)	[1]
Marketable Securities Estimate Fair Value		67,302		31,910	[1]
Amortized Cost		121,143		68,185
Gross Unrealized Gains				30
Gross Unrealized Losses		(5)		(1)
Estimate Fair Value		121,138		68,214
Foreign Government Agency Bonds
Assets
Marketable Securities	[2]	4,015
Marketable Securities Amortized Cost	[2]	4,015
Marketable Securities Estimate Fair Value	[2]	4,015
Corporate Bonds
Assets
Marketable Securities		51,027		31,910
Marketable Securities Amortized Cost		51,027		31,881
Marketable Securities Gross Unrealized Gains				30
Marketable Securities Gross Unrealized Losses				(1)
Marketable Securities Estimate Fair Value		51,027		31,910
Asset Backed Securities
Assets
Marketable Securities		12,260
Marketable Securities Amortized Cost		12,265
Marketable Securities Gross Unrealized Losses		(5)
Marketable Securities Estimate Fair Value		12,260
Money Market Funds
Assets
Money market funds	[3]	53,836		36,304
Amortized Cost		53,836	[3]	36,304	[1]
Estimate Fair Value		53,836	[3]	36,304	[1]
Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Total fair value of assets		53,836		36,304
Quoted Prices in Active Markets for Identical Assets (Level 1) | Money Market Funds
Assets
Money market funds	[3]	53,836		36,304
Significant Other Observable Inputs (Level 2)
Assets
Marketable Securities		67,302		31,910
Total fair value of assets		67,302		31,910
Significant Other Observable Inputs (Level 2) | Foreign Government Agency Bonds
Assets
Marketable Securities	[2]	4,015
Significant Other Observable Inputs (Level 2) | Corporate Bonds
Assets
Marketable Securities		51,027		$ 31,910
Significant Other Observable Inputs (Level 2) | Asset Backed Securities
Assets
Marketable Securities		$ 12,260
[1]	Included in cash and cash equivalents on the balance sheet.
[2]	Consists of short-term agency bonds of Asian Development Bank
[3]	Included in cash and cash equivalents on the balance sheet

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Details) - USD ($)	Jun. 30, 2021	Dec. 31, 2020
Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of financial liabilities measured and recognized	$ 0	$ 0

Accrued and Other Current Lia_3

Accrued and Other Current Liabilities - Schedule of Accrued and Other Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Payables And Accruals [Abstract]
Accrued salaries and benefits	$ 1,056	$ 1,330
Accrued research and development expenses	970	910
Accrued professional services	279	232
Accrued interest	10	16
Other	91	187
Total	$ 2,406	$ 2,675

Long-Term Debt - Additional Inf

Long-Term Debt - Additional Information (Details) - USD ($)	Oct. 26, 2018	Jun. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Long-term debt net of debt discount and issuance costs		$ 1,833,000
Loan Agreement | Silicon Valley Bank
Debt Instrument [Line Items]
Debt instrument, maximum borrowing capacity	$ 10,000,000
Debt instrument, increments amount	$ 1,000,000
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		2,100,000
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 Loans
Debt Instrument [Line Items]
Debt instrument, remaining borrowing capacity	$ 5,000,000

Long-Term Debt - Summary of Fut

Long-Term Debt - Summary of Future Contractual Maturities of Debt (Details) $ in Thousands	Jun. 30, 2021USD ($)
Debt Disclosure [Abstract]
2021 (remaining six months)	$ 1,000
2022	833
Total future maturities of debt	$ 1,833

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2021	Jan. 31, 2021	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Sep. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares issued in first offering period	2,464,788
2016 Incentive Award Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options term			10 years
Options and restricted stock awards vesting period			4 years
Weighted average grant-date fair value of options granted			$ 3.85	$ 17.33
Unrecognized stock-based compensation expense			$ 12.1
Unrecognized stock-based compensation expense, weighted-average recognition period			2 years 7 months 6 days
Fair value of options vested			$ 4.9	$ 0.5
2016 Incentive Award Plan | Incentive Stock Options | 10% Stockholder
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Estimated fair value shares date of grant, maximum			10.00%
2016 Incentive Award Plan | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise price, percent of estimated fair value of shares on date of grant			100.00%
2016 Incentive Award Plan | Minimum | Incentive Stock Options | 10% Stockholder
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise price, percent of estimated fair value of shares on date of grant			110.00%
2016 Incentive Award Plan | Maximum | 10% Stockholder
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock options term			5 years
2019 Incentive Award Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Increase in number of common stock shares available for Issuance		697,479
2019 Employee Share Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, shares reserved for issuance		174,369	493,423			160,000
Employee share purchase plan offering period			6 months 15 days
Shares issued in first offering period					14,766
Employee share purchase plan new offering period			5 months 15 days
Employee share purchase plan new offering period, description			A new offering period running 5.5 months has been authorized beginning July 1, 2021 through December 15, 2021.

Stock-Based Compensation - Sche

Stock-Based Compensation - Schedule of Activity Under 2019 Plan and 2016 Plan (Details) - 2019 and 2016 Incentive Award Plan - $ / shares	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares Available for Grant, Beginning Balance	844,475
Shares Available for Grant, Additional shares authorized	697,479
Shares Available for Grant, Options granted	(36,000)
Shares Available for Grant, Ending Balance	1,505,954	844,475
Outstanding Options, Number of Shares, Beginning Balance	3,162,459
Outstanding Options, Number of Shares, Options granted	36,000
Outstanding Options, Number of Shares, Options exercised	(7,932)
Outstanding Options, Number of Shares, Ending Balance	3,190,527	3,162,459
Outstanding Options, Number of Shares, Exercisable as of March 31, 2021	1,259,176
Outstanding Options, Number of Shares, Vested and expected to vest, March 31, 2021	3,190,527
Outstanding Options, Weighted Average Exercise Price, Beginning Balance	$ 9.31
Outstanding Options, Weighted Average Exercise Price, Options granted	5.01
Outstanding Options, Weighted Average Exercise Price, Options exercised	1.04
Outstanding Options, Weighted Average Exercise Price, Ending Balance	9.28	$ 9.31
Shares Available for Grant, Exercisable as of March 31, 2021	7.84
Shares Available for Grant, Vested and expected to vest, March 31, 2021	$ 9.28
Weighted Average Remaining Contractual Term, Balance	8 years 3 months 21 days	8 years 9 months 14 days
Weighted Average Remaining Contractual Term, Options granted	9 years 10 months 24 days
Weighted Average Remaining Contractual Term, Exercisable as of March 31, 2021	7 years 5 months 8 days
Weighted Average Remaining Contractual Term, Vested and expected to vest, March 31, 2021	8 years 3 months 21 days

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Stock Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 1,434	$ 924	$ 2,903	$ 1,373
Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	452	331	896	516
General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Stock-based compensation expense	$ 982	$ 593	$ 2,007	$ 857

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				6 Months Ended
	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020
Numerator:
Net loss attributable to common stockholders	$ (11,832)	$ (10,457)	$ (11,269)	$ (11,773)	$ (22,289)	$ (23,042)
Denominator:
Weighted-average shares used in computing net loss per share attributable to common stockholders, basic and diluted	31,529,417		17,394,466		26,778,804	17,388,741
Net loss per share attributable to common stockholders, basic and diluted	$ (0.38)		$ (0.65)		$ (0.83)	$ (1.33)

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	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities outstanding	3,190,527	2,195,775
Options to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities outstanding	3,190,527	2,190,659
Warrants to Purchase Common Stock
Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items]
Potentially dilutive securities outstanding		5,116

Related Party Transactions - Ad

Related Party Transactions - Additional Information (Details) $ in Thousands	1 Months Ended	3 Months Ended
	Mar. 31, 2021USD ($)Stockholdershares	Mar. 31, 2021USD ($)
Related Party Transactions [Abstract]
Number of existing stockholders of company affiliated directors purchased common stock | Stockholder	2
Issuance of common stock, net of issuance costs, Shares | shares	2,464,788
Issuance of common stock, net of issuance costs | $	$ 14,000	$ 75,215

Commitments and Contingencies -

Commitments and Contingencies - Schedule of Future Minimum Lease Payments Under Non-cancelable Operating Leases (Details) $ in Thousands	Jun. 30, 2021USD ($)
Operating Lease Liabilities Payments Due [Abstract]
2021 (remaining six months)	$ 121
2022	93
Total minimum lease payments	$ 214

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Income Tax Disclosure [Abstract]
Income tax provision	$ 0	$ 0