Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue	$ 114,610	$ 105,555	$ 113,420
Operating expenses:
Cost of product revenue	28,747	31,280	27,364
Research & development	16,665	18,190	18,787
Selling, general & administrative	34,950	34,336	21,540
Total operating expenses	80,362	83,806	67,691
Income from operations	34,248	21,749	45,729
Interest and other income, net	1,873	1,458	473
Income before income taxes	36,121	23,207	46,202
Provision for income taxes	8,928	4,485	14,386
Net income	$ 27,193	$ 18,722	$ 31,816
Basic net income per share:
Net income (in dollars per share)	$ 1.93	$ 1.30	$ 2.18
Basic weighted average common shares outstanding (in shares)	14,121	14,442	14,575
Diluted net income per share:
Net income (in dollars per share)	$ 1.89	$ 1.27	$ 2.11
Diluted weighted average common shares outstanding (in shares)	14,374	14,689	15,068
Net income	$ 27,193	$ 18,722	$ 31,816
Foreign currency translation adjustment	(372)	(742)	2,533
Comprehensive income	26,821	17,980	34,349
Product [Member]
Revenue	114,512	105,531	107,783
Service [Member]
Revenue	$ 98	$ 24	$ 5,637