Condensed Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 168	$ 180
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, authorized	5,000,000	5,000,000
Preferred stock, issued	0	0
Preferred stock, outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, authorized	200,000,000	200,000,000
Common stock, issued	27,020,070	26,561,504
Common stock, outstanding	27,020,070	26,561,504