Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating Activities
Net loss	$ (22,438)	$ (4,053)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	1,026	805
Depreciation and amortization	45	25
Changes in operating assets and liabilities:
Accounts receivable	2,307	13,634
Prepaid and other current assets	(1,671)	1,880
Accounts payable	(2,969)	(2,963)
Accrued compensation and other accrued liabilities	(31)	866
Operating lease liability and right-of-use asset	26	16
Deferred revenue	(651)	(15,000)
Net cash flows used in operating activities	(24,356)	(4,790)
Investing Activities
Proceeds from maturities of short-term investments	27,581	33,457
Purchase of short-term investments		(6,019)
Purchases of property and equipment		(17)
Net cash flows provided by investing activities	27,581	27,421
Financing Activities
Issuance of common stock for public offering, net of issuance costs	49,277	32,025
Issuance of common stock from stock grants and option exercises	182	339
Net cash flow provided by financing activities	49,459	32,364
Net increase in cash and cash equivalents	52,684	54,995
Cash and cash equivalents at beginning of the period	30,360	15,369
Cash and cash equivalents at end of the period	$ 83,044	$ 70,364