Condensed Consolidated Statements of Cash Flow (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating activities
Net (loss) income	$ (22,643)	$ 29,248
Adjustments to reconcile net (loss) income to net cash used in operating activities:
Gain from sale of priority review voucher		(46,493)
Income related to asset purchase agreement		(281)
Depreciation and amortization	73	67
Stock-based compensation	2,047	1,549
Amortization of debt securities premiums and discounts	330	191
Non-cash interest expense	200	199
Amortization of operating lease right-of-use assets	132	127
Common stock issued under Product Development Agreement	19	53
Change in operating assets and liabilities:
Accounts receivable	289	(639)
Inventories	666	(1,304)
Prepaid expenses and other current assets	(854)	1,529
Other assets	(397)	(18)
Accounts payable	1,269	3,175
Accrued liabilities	560	(2,205)
Operating lease liabilities	(150)	(131)
Net cash used in operating activities	(18,459)	(14,933)
Investing activities
Purchase of debt securities available-for-sale	(10,902)	(2,049)
Proceeds from maturities of debt securities available-for-sale	7,900	49,755
Proceeds from sale of priority review voucher		95,000
Payments related to priority review voucher		(48,507)
Proceeds related to asset purchase agreement		281
Purchase of property and equipment		(16)
Net cash (used in) provided by investing activities	(3,002)	94,464
Financing activities
Issuance of common stock upon offering at-the-market, net of commissions	45,610
Proceeds from issuance of common stock upon stock option exercises	144	166
Proceeds from issuance of common stock upon ESPP purchase	64	146
Common stock offering costs	(16)	(122)
Payment of debt issuance costs		(175)
Net cash provided by financing activities	45,802	15
Net increase in cash and cash equivalents	24,341	79,546
Cash and cash equivalents at beginning of period	22,221	28,864
Cash and cash equivalents at end of period	46,562	108,410
Supplemental disclosure of cash flow information:
Interest paid	686	$ 686
Income taxes paid	$ 41