Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net loss	$ (17,273)	$ (18,639)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation	160	113
Amortization of intangible assets	166	167
Stock-based compensation	2,007	6,965
Net premium amortization and discount on available-for-sale securities		13
Changes in operating assets and liabilities:
Accounts receivable	40
Inventory	(1,663)	(1,135)
Prepaid expenses and other current assets	191	(124)
Other receivables	(39)	48
Right-of-use assets	174	158
Accounts payable	609	433
Accrued expenses	215	291
Lease liabilities	(182)	(95)
Accrued interest on note payable	1	118
Net cash used in operating activities	(15,594)	(11,687)
Cash flows from investing activities:
Purchases of property and equipment	(279)	(51)
Maturities of investments		8,000
Net cash provided by (used in) investing activities	(279)	7,949
Cash flows from financing activities:
Proceeds from issuance of common stock under employee stock purchase plan	372	430
Proceeds from exercises of warrants		4,217
Proceeds from exercises of stock options		619
Proceeds from issuance of common stock		4,892
Proceeds from issuance of related party note		41,000
Payments made on insurance loan agreement	(437)
Net cash provided by (used in) financing activities	(65)	51,158
Net increase (decrease) in cash and cash equivalents	(15,938)	47,420
Cash and cash equivalents at beginning of period	28,614	12,463
Cash and cash equivalents at end of period	12,676	59,883
Supplemental disclosure of noncash investing and financing activities:
Equipment purchases included in accounts payable and accrued expenses	$ (27)	14
Change in unrealized gains on available-for-sale securities		1
Other receivable from issuance of common stock from at-the-market equity offering		$ (71)