CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash Flows from Operating Activities:
Net income (loss)	$ 102,210	$ (35,961)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Stock-based compensation	1,990	2,273
Warrant liability revaluation gain	(6,983)	495
Future tranche right liability revaluation gain	(118,803)	6,988
Issuance of common stock for services rendered	130	170
Accretion of discounts on short-term investments	(1)	(43)
Depreciation and amortization expense	17	52
Changes in operating assets and liabilities:
Prepaid expenses and other assets	1,930	1,215
Accounts payable, accrued expenses, and other liabilities	(1,040)	(1,391)
Other	5	10
Net cash used in operating activities	(20,545)	(26,192)
Cash Flows from Investing Activities:
Purchases of available-for-sale securities		(12,180)
Proceeds from maturity of available-for-sale securities	4,500	8,350
Purchases of property and equipment		(7)
Net cash provided by (used in) investing activities	4,500	(3,837)
Cash Flows from Financing Activities:
Proceeds from common stock financings, net	19,534	12,258
Proceeds from employee stock purchases	48	84
Proceeds from exercise of common stock options and warrants	271
Payments on seller-financed purchases	(435)
Net cash provided by financing activities	19,418	12,342
Net increase (decrease) in cash and cash equivalents	3,373	(17,687)
Cash and cash equivalent, beginning of period	33,229	40,019
Cash and cash equivalents, end of period	36,602	22,332
Supplemental disclosure of cash flow information:
Cash paid for interest	$ 5
Supplemental disclosure of non-cash financing and investing activities:
Offering costs in accounts payable and accrued expenses		$ 91