CONSOLIDATED STATEMENTS OF INCOME - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Income Statement [Abstract]
REVENUE	$ 43,572,000	$ 55,566,000
COST OF SALES	7,458,000	12,987,000
Gross margin	36,114,000	42,579,000
OPERATING EXPENSES:
Research and development	12,357,000	11,818,000
Selling, general and administrative	10,791,000	10,077,000
Amortization of acquired technology and other intangible assets	5,491,000	5,492,000
Patent costs	1,725,000	1,547,000
Royalty and license expense	1,231,000	1,587,000
Total operating expenses	31,595,000	30,521,000
OPERATING INCOME	4,519,000	12,058,000
Interest income, net	1,271,000	671,000
Other expense, net	(47,000)	(19,000)
Interest and other expense, net	1,224,000	652,000
INCOME BEFORE INCOME TAXES	5,743,000	12,710,000
INCOME TAX BENEFIT (EXPENSE)	216,000	(2,345,000)
NET INCOME	$ 5,959,000	$ 10,365,000
NET INCOME PER COMMON SHARE:
BASIC	$ 0.13	$ 0.22
DILUTED	$ 0.13	$ 0.22
WEIGHTED AVERAGE SHARES USED IN COMPUTING NET INCOME PER COMMON SHARE:
BASIC	46,783,158	46,661,559
DILUTED	46,848,798	46,742,894
CASH DIVIDENDS DECLARED PER COMMON SHARE	$ 0.06	$ 0.03