Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statements of Operations:
Revenue	$ 434,395	$ 458,728	$ 445,596
Cost of revenue	216,568	223,438	206,917
Gross profit	217,827	235,290	238,679
Operating expenses
Marketing and sales	69,309	72,976	68,533
Research and development	36,940	32,692	28,735
General and administrative	51,742	49,766	52,513
Total operating expenses	157,991	155,434	149,781
Income from operations	59,836	79,856	88,898
Other income, net	3,109	1,337	2,757
Income before income taxes	62,945	81,193	91,655
Provision for income taxes	12,078	17,538	15,067
Net income	$ 50,867	$ 63,655	$ 76,588
Net income per share:
Basic (in dollars per share)	$ 1.90	$ 2.37	$ 2.84
Diluted (in dollars per share)	$ 1.89	$ 2.35	$ 2.81
Shares used to compute net income per share:
Basic (in shares)	26,737,425	26,866,985	26,982,614
Diluted (in shares)	26,896,357	27,049,423	27,278,816
Other Comprehensive Income (Loss), net of tax
Foreign currency translation adjustments	$ 3,598	$ 1,474	$ (3,258)
Comprehensive income	$ 54,465	$ 65,129	$ 73,330