Condensed Consolidated Balance Sheets (Current Period Unaudited) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Cash and cash equivalents	$ 5,014	$ 4,937
Short-term investments	24,956	29,983
Accounts receivable, net	4,239	3,859
Inventories, net	1,870	1,566
Prepaid expenses and other current assets	735	868
Total current assets	36,814	41,213
Property and equipment, net	944	976
Operating lease right-of-use asset, net	362	51
Intangible assets, net	1,981	1,982
Other assets	11	9
Total assets	40,112	44,231
Current liabilities:
Accounts payable	1,727	1,779
Accrued liabilities	819	824
Customer deposits	0	43
Deferred revenue- short term	121	155
Operating lease liability- short term	96	56
Total current liabilities	2,763	2,857
Long-term liabilities:
Deferred revenue- long term	161	110
Operating lease liability - long term	275	0
Total long-term liabilities	436	110
Total liabilities	3,199	2,967
Commitments and contingencies (Note 12)
Stockholders' equity:
Preferred stock - 5,000,000 authorized; par value $0.0001 per share; none issued and outstanding	0	0
Common stock - 150,000,000 authorized; par value $0.0001 per share; 40,951,197 and 40,851,945 shares issued and outstanding each period, respectively	4	4
Additional paid-in capital	92,129	91,025
Accumulated deficit	(55,191)	(49,759)
Accumulated other comprehensive income	(29)	(6)
Total stockholders' equity	36,913	41,264
Total liabilities and stockholders' equity	$ 40,112	$ 44,231