Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities:
Net income	$ 30,758,000	$ 38,319,000	$ 20,575,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	3,775,000	4,706,000	4,772,000
Stock-based compensation expense	2,225,000	1,607,000	1,268,000
Deferred income taxes	(747,000)	$ 815,000	2,206,000
Provision for doubtful accounts	38,000		238,000
Provision for inventory	$ 210,000	$ 378,000	171,000
Gain on sale of assets			(126,000)
Tax benefit from equity awards	$ (847,000)	$ (9,626,000)	$ (857,000)
Non-cash impairment charges for IPR&D	$ 697,000
Restructuring credits			$ (161,000)
Changes in operating assets and liabilities:
Accounts receivable	$ (4,996,000)	$ 898,000	2,411,000
Inventories	(2,939,000)	(1,974,000)	(2,823,000)
Prepaid expenses, other current and long-term assets	89,000	585,000	307,000
Accounts payable	5,625,000	(750,000)	623,000
Accrued expenses	(199,000)	(1,189,000)	(377,000)
Deferred revenue	(15,000)	(2,014,000)	(2,795,000)
Income taxes payable	5,484,000	8,436,000	152,000
Other long-term liabilities	(94,000)	(213,000)	(419,000)
Net cash provided by operating activities	39,064,000	39,978,000	$ 25,165,000
Cash flows from investing activities:
Proceeds from maturity of investments	24,250,000	20,000,000
Purchase of investments	(45,251,000)	(26,750,000)
Purchase of property and equipment	$ (9,225,000)	$ (1,553,000)	$ (441,000)
Proceeds from sale of assets			188,000
Net cash used in investing activities	$ (30,226,000)	$ (8,303,000)	(253,000)
Cash flows from financing activities:
Principal payments on debt			(9,600,000)
Proceeds from exercise of equity awards	$ 1,074,000	$ 2,055,000	3,054,000
Tax benefit from equity awards	$ 847,000	9,626,000	$ 857,000
Minimum tax withholdings on share-based awards		(6,349,000)
Net cash provided by financing activities	$ 1,921,000	5,332,000	$ (5,689,000)
Exchange rate impact on cash	(208,000)	(184,000)	43,000
Increase in cash and cash equivalents	10,551,000	36,823,000	19,266,000
Cash and cash equivalents at beginning of period	100,156,000	63,333,000	44,067,000
Cash and cash equivalents at end of period	110,707,000	100,156,000	63,333,000
Supplemental disclosure of cash flow information:
Cash paid for income taxes	$ 12,724,000	$ 13,778,000	9,842,000
Cash paid for interest			126,000
Non-cash Investing Activities:
Purchases of property and equipment included in accounts payable and accrued expenses	$ 1,949,000	$ 52,000	$ 364,000