CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Consolidated Statements Of Operations [Abstract]
Revenue	$ 61,511	$ 77,476	$ 122,403	$ 150,572
Cost of revenue	29,600	35,740	58,473	66,415
Gross profit	31,911	41,736	63,930	84,157
Operating expenses:
Research and development	13,056	12,733	25,774	24,516
Selling, general and administrative	13,050	11,946	24,356	24,739
Amortization	387	383	774	763
Total operating expenses	26,493	25,062	50,904	50,018
Operating income	5,418	16,674	13,026	34,139
Interest income, net	(860)	(476)	(1,666)	(867)
Other expense (income), net	157	(140)	(224)	42
Income before income taxes	6,121	17,290	14,916	34,964
Provision for income taxes	595	2,593	1,814	5,137
Net income	$ 5,526	$ 14,697	$ 13,102	$ 29,827
Earnings per share:
Basic	$ 0.18	$ 0.46	$ 0.42	$ 0.94
Diluted	$ 0.18	$ 0.45	$ 0.42	$ 0.92
Weighted average shares outstanding:
Basic	31,126	31,859	31,058	31,760
Diluted	31,398	32,437	31,369	32,377