Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 2,062	$ (23,877)	$ (12,348)
Available-for-sale investments
Net change in unrealized gain (loss) on available-for-sale investments	0	(3)	9
Less: Reclassification adjustment for net losses on investments recognized during the year	0	63	0
Total change in unrealized gain (loss) on available-for-sale investments	0	60	9
Other comprehensive income, net of tax	0	60	9
Comprehensive income (loss)	$ 2,062	$ (23,817)	$ (12,339)