Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net loss	$ (74,894,000)	$ (51,853,000)	$ (18,606,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Noncash inventory reserve	5,323,000
Depreciation	2,064,000	105,000	18,000
Amortization	159,000	171,000	145,000
Noncash stock-based compensation	3,338,000	2,818,000	1,762,000
Noncash interest	1,661,000	1,341,000
Changes in operating assets and liabilities:
Accounts receivable	(668,000)	(865,000)
Inventory	(6,289,000)
Prepaid expenses and other assets	(967,000)	(2,485,000)	(233,000)
Accounts payable and accrued expenses	5,202,000	3,641,000	1,377,000
Lease liability	(131,000)	(184,000)	(152,000)
Net cash used in operating activities	(65,202,000)	(47,311,000)	(15,689,000)
Cash flows from investing activities:
Purchases of marketable securities		(54,837,000)
Sales and maturities of marketable securities	39,729,000	14,500,000
Acquisition of property and equipment	(269,000)	(353,000)	(98,000)
Net cash provided by (used in) investing activities	39,460,000	(40,690,000)	(98,000)
Cash flows from financing activities:
Proceeds from issuance of common stock in private placement, net of offering costs			7,810,000
Proceeds from issuance of long-term debt		20,000,000
Debt financing costs paid		(1,059,000)
Proceeds from exercise of stock options	75,000	610,000	164,000
Net cash provided by financing activities	30,422,000	67,985,000	42,415,000
Net increase (decrease) in cash and cash equivalents	4,680,000	(20,016,000)	26,628,000
Cash and cash equivalents, beginning of period	14,463,000	34,479,000	7,851,000
Cash and cash equivalents, end of period	19,143,000	14,463,000	34,479,000
Supplemental disclosure of noncash financing activities
Warrants issued in connection with long-term debt	1,080,000	3,570,000
Operating right-of-use assets obtained in exchange for new operating lease liabilities	969,000
Supplemental cash flow information
Interest paid	2,383,000	2,099,000
Non-cash transactions
Property and equipment purchases included in accounts payable			49,000
Public offering
Cash flows from financing activities:
Proceeds from issuance of common stock, net of offering costs	21,081,000	$ 48,434,000	12,687,000
At-the-market sales
Cash flows from financing activities:
Proceeds from At-the-Market sales of common stock, net of offering costs	$ 9,266,000		$ 21,754,000