Condensed Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities
Net loss	$ (28,100)	$ (22,856)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation expense	455	359
Stock-based compensation expense	3,531	2,578
Non-cash operating lease expense	244	348
Other	272	271
Changes in operating assets and liabilities:
Accounts receivable	749	7,105
Prepaid expenses and other current assets	1,013	318
Other non-current assets	207	0
Accounts payable	1,770	665
Accrued liabilities	(364)	(2,092)
Operating lease liabilities	(275)	(361)
Net cash used in operating activities	(20,498)	(13,665)
Cash flows from investing activities
Purchase of short-term investments	(39,228)	(64,806)
Maturity of short-term investments	41,403	77,280
Purchase of property and equipment	(644)	(242)
Net cash provided by investing activities	1,531	12,232
Cash flows from financing activities
Proceeds from exercise of stock options	51	1,370
Payment of deferred offering costs	(204)	0
Net cash (used in) provided by financing activities	(153)	1,370
Net decrease in cash and cash equivalents	(19,120)	(63)
Cash and cash equivalents at beginning of period	51,665	50,882
Cash and cash equivalents at end of period	32,545	50,819
Supplemental disclosures of noncash investing and financing activities:
Purchase of property and equipment in accounts payable and accrued liabilities	0	251
Reclassification of restricted stock awards from liabilities to common stock upon vesting	1	2
Net unrealized (loss) gain on short-term investments	$ (749)	$ 14