Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Net income (loss)	$ 15,101	$ (6,956)
Adjustments to reconcile to net cash provided by (used in) operating activities:
Stock-based compensation expense	8,018	9,945
Depreciation and amortization	20,097	17,770
Deferred income taxes	4,951	547
Change in fair value of contingent obligations	433	935
Impairment of equipment charge	0	1,114
Excess tax benefits from stock-based compensation	0	(10,442)
Other	464	775
Changes in operating assets and liabilities:
Accounts receivable	36,160	53,933
Inventories	3,473	(19,738)
Income taxes	0	(10,064)
Prepaid expenses and other assets	276	(1,713)
Accounts payable	4,245	11,287
Accrued expenses and other liabilities	(4,386)	(3,533)
Accrued compensation	(10,194)	(4,966)
Provision for chargebacks	0	274
Deferred revenue	17,035	1,007
Net cash provided by operating activities	95,673	40,175
Cash flows from investing activities:
Purchases of property, plant and equipment	(29,605)	(39,246)
Net cash used in investing activities	(29,605)	(39,246)
Cash flows from financing activities:
Issuance of common stock upon exercise of stock options	4,605	14,524
Excess tax benefits from stock-based compensation	0	10,442
Taxes paid on behalf of employees for equity activity	(4,059)	(4,492)
Payments of notes payable	(20,000)	0
Contingent obligation payments	(2,405)	(971)
Purchase of treasury stock	(83)	0
Net cash (used in) provided by financing activities	(21,942)	19,503
Effect of exchange rate changes on cash and cash equivalents	(12)	168
Net increase in cash and cash equivalents	44,114	20,600
Cash and cash equivalents at beginning of period	271,513	312,795
Cash and cash equivalents at end of period	$ 315,627	$ 333,395