CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Statement [Abstract]
REVENUE	$ 97,515	$ 77,550	$ 303,448	$ 177,271
COST OF SALES	17,286	16,123	57,172	35,216
Gross margin	80,229	61,427	246,276	142,055
OPERATING EXPENSES:
Research and development	16,787	13,616	51,449	38,922
Selling, general and administrative	12,623	12,120	40,531	34,473
Amortization of acquired technology and other intangible assets	5,493	5,493	16,469	16,479
Patent costs	1,659	1,937	5,145	5,691
Royalty and license expense	2,837	2,229	8,828	5,028
Total operating expenses	39,399	35,395	122,422	100,593
OPERATING INCOME	40,830	26,032	123,854	41,462
Interest income, net	2,748	2,118	8,336	5,155
Other income (expense), net	53	(7)	740	(66)
Interest and other income, net	2,801	2,111	9,076	5,089
INCOME BEFORE INCOME TAXES	43,631	28,143	132,930	46,551
INCOME TAX EXPENSE	(6,669)	(5,325)	(21,054)	(6,960)
NET INCOME	$ 36,962	$ 22,818	$ 111,876	$ 39,591
NET INCOME PER COMMON SHARE:
BASIC	$ 0.78	$ 0.48	$ 2.36	$ 0.83
DILUTED	$ 0.78	$ 0.48	$ 2.36	$ 0.83
WEIGHTED AVERAGE SHARES USED IN COMPUTING NET INCOME PER COMMON SHARE:
BASIC	46,980,439	46,869,998	46,947,109	46,841,036
DILUTED	47,013,919	46,914,553	46,983,901	46,893,768
CASH DIVIDENDS DECLARED PER COMMON SHARE	$ 0.10	$ 0.06	$ 0.30	$ 0.18