Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net income	$ 24,462	$ 19,715
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	2,777	2,800
Stock-based compensation expense	2,276	1,562
Deferred income taxes	(571)	(16)
Provision for doubtful accounts	52
Provision for inventory	259	149
Tax benefit from equity awards	(421)	(877)
Changes in operating assets and liabilities:
Accounts receivable	(104)	(6,550)
Inventories	(3,229)	82
Prepaid expenses, other current and long-term assets	355	403
Accounts payable	(5,390)	970
Accrued expenses and other current liabilities	1,091	(120)
Deferred revenue	(43)	(9)
Income taxes payable	(3,496)	5,757
Other long-term liabilities	(61)	(76)
Net cash provided by operating activities	17,957	23,790
Cash flows from investing activities:
Proceeds from maturity of investments	37,750	14,750
Purchase of investments	(32,250)	(30,009)
Purchase of property and equipment	(12,608)	(2,028)
Net cash used in investing activities	(7,108)	(17,287)
Cash flows from financing activities:
Repurchases of common stock	(25,000)
Proceeds from exercise of equity awards	988	1,075
Tax benefit from equity awards	421	877
Net cash (used in) provided by financing activities	(23,591)	1,952
Exchange rate impact on cash	82	(142)
Increase (decrease) in cash and cash equivalents	(12,660)	8,313
Cash and cash equivalents at beginning of period	110,707	100,156
Cash and cash equivalents at end of period	98,047	108,469
Non-cash Investing Activities:
Purchases of property and equipment included in accounts payable and accrued expenses	474	2,197
Build-to-suite lease agreement	$ 1,825