CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
REVENUE	$ 112,277	$ 87,765
COST OF SALES	22,459	15,814
Gross margin	89,818	71,951
OPERATING EXPENSES:
Research and development	19,497	15,829
Selling, general and administrative	15,403	11,969
Amortization of acquired technology and other intangible assets	5,490	5,486
Patent costs	1,638	1,770
Royalty and license expense	3,284	2,537
Total operating expenses	45,312	37,591
OPERATING INCOME	44,506	34,360
Interest income, net	2,147	2,831
Other income, net	202	282
Interest and other income, net	2,349	3,113
INCOME BEFORE INCOME TAXES	46,855	37,473
INCOME TAX EXPENSE	(8,700)	(5,999)
NET INCOME	$ 38,155	$ 31,474
NET INCOME PER COMMON SHARE:
BASIC	$ 0.80	$ 0.66
DILUTED	$ 0.80	$ 0.66
WEIGHTED AVERAGE SHARES USED IN COMPUTING NET INCOME PER COMMON SHARE:
BASIC	47,093,033	46,892,914
DILUTED	47,122,829	46,931,999
CASH DIVIDENDS DECLARED PER COMMON SHARE	$ 0.15	$ 0.10