Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets
Cash and cash equivalents	$ 19,300	$ 24,205
Accounts receivable	951	750
Inventories	3,294	2,843
Other current assets	350	328
Total current assets	23,895	28,126
Property, plant and equipment, net	1,153	1,188
Operating lease right-of-use asset	1,038	1,082
Other assets	21	21
TOTAL ASSETS	26,107	30,417
Current liabilities
Accounts payable	1,797	1,414
Accrued compensation	1,335	1,664
Current portion of operating lease liability	181	167
Current portion of finance lease liability	24	26
Other current liabilities	55	36
Total current liabilities	3,392	3,307
Operating lease liability	909	956
Finance lease liability	22	28
Other long-term liability	71	179
Total liabilities	4,394	4,470
Commitments and contingencies
Stockholders' equity
Preferred stock	0	0
Common stock as of March 31, 2022 and December 31, 2021, par value $0.0001 per share; authorized 100,000,000 shares, issued and outstanding 10,537,606 shares	1	1
Additional paid-in capital	279,114	278,873
Accumulated other comprehensive income:
Foreign currency translation adjustment	(13)	(11)
Accumulated deficit	(257,389)	(252,916)
Total stockholders' equity	21,713	25,947
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	26,107	30,417
Series A Junior Participating Preferred Stock [Member]
Stockholders' equity
Preferred stock	0	0
Series F Convertible Preferred Stock [Member]
Stockholders' equity
Preferred stock	$ 0	$ 0