UNAUDITED CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Current assets:
Accounts receivable, allowances for bad debts and customer credits	$ 326	$ 406
Stockholders' equity:
Common stock, par value	$ 0.001	$ 0.001
Common stock, authorized	55,000,000	55,000,000
Common stock, issued	13,465,871	13,169,204
Common stock, outstanding	13,465,871	13,169,204
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, authorized	11,445,187	11,445,187
Series A
Stockholders' equity:
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, authorized	2,000,000	2,000,000
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0