CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 17,897	$ 25,580
Marketable securities	54,104	66,872
Accounts receivable	11,724	5,934
Inventory	16,714	14,859
Prepaid expenses and other current assets	5,356	5,460
Total current assets	105,795	118,705
Property and equipment, net	12,044	9,841
Restricted cash	500	500
Operating lease right-of-use assets	5,669	5,847
Total assets	124,008	134,893
Current liabilities:
Accounts payable	2,934	6,651
Accrued expenses and other current liabilities	15,738	16,337
Deferred revenue	247	250
Operating lease liabilities	1,337
Total current liabilities	20,256	23,238
Long-term debt, net of discount and current portion	35,334	35,197
Operating lease liabilities, net of current portion	8,508	8,604
Total liabilities	64,098	67,039
Commitments and contingencies (Note 9)
Stockholders' equity:
Preferred stock, no par value; 25,000,000 shares authorized; no shares issued or outstanding
Common stock, no par value; 150,000,000 shares authorized; 27,968,583 shares and 27,791,615 shares issued and outstanding at March 31, 2022 and December 31, 2021, respectively	513,203	510,488
Accumulated other comprehensive loss	(285)	(188)
Accumulated deficit	(453,008)	(442,446)
Total stockholders' equity	59,910	67,854
Total liabilities and stockholders' equity	$ 124,008	$ 134,893