Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities:
Net loss	$ (708,373)	$ (119,172)	$ (352,746)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	21,974	31,042	34,837
Asset impairment charges	392,097	0	29,413
Impairment on divestiture	0	0	133,273
Amortization of debt discount	26,868	26,182	23,676
Unrealized foreign currency transaction losses (gains), net	2,180	(941)	(173)
Stock compensation expense	31,520	30,987	30,605
Loss on disposal of fixed assets	105	521	543
Deferred tax benefit	(89,895)	(23)	(53,292)
Extinguishment of debt	0	5,380	0
Gain on sale of businesses	0	(289,305)	0
Gain on sale of investment	0	0	(19,773)
Gain on remeasurement of equity investment	0	0	(22,597)
Reserve for excess or obsolete inventory	17,453	8,533	42,599
Changes in contingent purchase price	(18,787)	23,981	20,278
Changes in operating assets and liabilities:
Accounts receivable	9,180	30,144	103,100
Inventory, net	6,511	(15,653)	(69,318)
Prepaid expenses and other assets	534	569	(5,286)
Accounts payable	(17,222)	(7,398)	16,362
Accrued expenses	31,526	(37,233)	(39,501)
Deferred revenue	(13,757)	1,568	8,386
Payments on contingent purchase price	(52,543)	(1,045)	(78,900)
Other liabilities	(7,659)	(11,446)	549
Net cash used in operating activities	(368,288)	(323,309)	(197,965)
Cash flows from investing activities:
Purchases of available for sale securities	(131,560)	0
Proceeds from sale of fixed assets	0	0	250
Proceeds from sale of investment	0	0	19,773
Proceeds from maturities and sales of available for sale securities	131,535	0
Purchases of fixed assets	(4,525)	(2,176)	(2,555)
Payments for intangible assets	0	(10,000)	(112,617)
Acquisition of business, net of cash acquired	0	0	(28,397)
Proceeds from sale of businesses	0	437,875	0
Change in restricted cash	(478)	(3,656)	35
Net cash (used in) provided by investing activities	(5,028)	422,043	(123,511)
Cash flows from financing activities:
Proceeds from issuances of common stock, net	48,621	33,776	95,198
Payments on contingent purchase price	(10,523)	(9,404)	(157,601)
Proceeds from the issuance of convertible senior notes	0	402,500	400,000
Repayments of convertible senior notes	(55,000)	(323,225)	0
Purchase of capped call transactions related to convertible senior notes	0	(33,931)	0
Proceeds from settlement of bond hedges related to convertible senior notes	0	100,459	0
Settlement of warrants	(2)	(87,874)	0
Debt and equity issuance costs	0	(11,725)	(12,769)
Purchase of shares of non-controlling interest	(167)	0	0
Net cash (used in) provided by financing activities	(17,071)	70,576	324,828
Effect of exchange rate changes on cash	(89)	(648)	(920)
(Decrease) increase in cash and cash equivalents	(390,476)	168,662	2,432
Cash and cash equivalents at beginning of period	541,835	373,173	370,741
Cash and cash equivalents at end of period	151,359	541,835	373,173
Supplemental disclosure of cash flow information:
Interest paid	22,561	12,269	8,837
Taxes paid	575	36	114
Non-cash investing and financing activities
Issuance of common stock upon conversion of convertible notes	32,018	0	0
Receipt of common stock upon settlement of 2017 Note hedge	40,015	0	0
Issuance of common stock upon the exercise of the 2017 Warrants	$ 1,638	$ 0	$ 0