Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Current assets:
Allowance for doubtful accounts	$ 288	$ 275
Stockholders' equity:
Series C Convertible Preferred Stock, par value (in dollars per share)	$ 0.10	$ 0.10
Series C Convertible Preferred Stock, shares authorized (in shares)	10,000,000	10,000,000
Series C Convertible Preferred Stock, shares issued (in shares)	0	0
Series C Convertible Preferred Stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, shares issued (in shares)	34,723,046	34,364,679
Common stock, shares outstanding (in shares)	34,723,046	34,364,679