Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock Class A common stock	Common Stock Class B common stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2018		15,789,000	18,109,000
Beginning balance at Dec. 31, 2018	$ 91,846	$ 2	$ 2	$ 157,898	$ (178)	$ (21,562)	$ (44,316)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)		14,000
Exercise of stock options	90	$ 0		90
Stock-based compensation	1,831			1,831
Vesting of restricted stock units, net of shares withheld for taxes (in shares)		58,000
Vesting of restricted stock units, net of shares withheld for taxes	(2,572)	$ 0		(2,572)
Vesting of early exercised shares	6			6
Conversion of Class B stock to Class A stock (in shares)		38,000	(38,000)
Conversion of Class B stock to Class A stock	0
Other comprehensive income	129				129
Net income	3,725						3,725
Ending balance (in shares) at Mar. 31, 2019		15,899,000	18,071,000
Ending balance at Mar. 31, 2019	95,055	$ 2	$ 2	157,253	(49)	(21,562)	(40,591)
Beginning balance (in shares) at Dec. 31, 2019		16,552,000	17,594,000
Beginning balance at Dec. 31, 2019	$ 131,950	$ 2	$ 2	161,509	33	(21,562)	(8,034)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)	17,000	17,000
Exercise of stock options	$ 97			97
Stock-based compensation	1,365			1,365
Vesting of restricted stock units, net of shares withheld for taxes (in shares)		91,000
Vesting of restricted stock units, net of shares withheld for taxes	(6,458)			(6,458)
Conversion of Class B stock to Class A stock (in shares)		58,000	(58,000)
Conversion of Class B stock to Class A stock	0
Other comprehensive income	$ 132				132
Repurchase of common stock (in shares)	(48,002)	(48,000)
Repurchase of common stock	$ (4,194)					(4,194)
Net income	1,983						1,983
Ending balance (in shares) at Mar. 31, 2020		16,670,000	17,536,000
Ending balance at Mar. 31, 2020	$ 124,875	$ 2	$ 2	$ 156,513	$ 165	$ (25,756)	$ (6,051)