CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities:
Net loss	$ (162,602)	$ (274,158)	$ (220,872)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation, amortization and impairment charges	8,814	4,136	8,307
Stock-based compensation	32,403	35,421	20,341
Deferred executive compensation expense	119	963	2,810
Gain on disposition of stock	(4,768)
Revaluation of warrant liability			15,924
Increase (decrease) from:
Accounts receivable	(7,092)	(1,305)
Inventory	(560)	(413)
Other current assets	(17,536)	(2,113)	(4,714)
Other assets	2,645	(2,714)
Accounts payable	(137)	2,478	2,664
Accrued compensation and benefits	8,317	913	10,656
Accrued product development expenses	(2,782)	2,679	2,113
Other accrued expenses	2,570	1,340	4,669
Other liabilities	2,644	14,834	5,714
Deferred revenue	82,801	10	(230)
Deferred executive compensation paid	(2,630)	(3,953)	(1,063)
Net cash used in operating activities	(57,794)	(221,882)	(153,681)
Cash flows from investing activities:
Acquisitions of marketable securities			(89,554)
Proceeds from maturities of marketable securities		45,000	44,500
Change in restricted cash		(10,319)	(289)
Investment in property and equipment	(2,787)	(8,543)	(4,424)
Gain on disposition of stock	4,768
Investment in intangible assets			(633)
Net cash provided by (used in) investing activities	1,981	26,138	(50,400)
Cash flows from financing activities:
Proceeds from issuance of convertible debt, including equity component, net of issuance costs, $7,079,000	192,921
Proceeds from issuance of warrants	27,580
Purchase of convertible bond hedges	(43,220)
Repayment of long-term borrowings	(9,100)	(2,100)	(1,400)
Principal payments under capital lease obligations		(15)	(54)
Proceeds from issuance of common stock, net of issuance costs		310,037
Reimbursements of amounts related to facility lease obligation		2,741
Proceeds from issuance of common stock pursuant to warrants			12,483
Proceeds from issuance of common stock pursuant to stock option and purchase plans	3,695	6,284	10,511
Payment of tax withholding obligations related to stock compensation	(816)	(3,363)	(4,336)
Net cash provided by financing activities	171,060	313,584	17,204
Effect of exchange rates on cash	262	(40)
Net increase (decrease) in cash and cash equivalents	115,509	117,800	(186,877)
Cash and cash equivalents, beginning of year	237,179	119,379	306,256
Cash and cash equivalents, end of year	352,688	237,179	119,379
Supplemental disclosures:
Interest paid	8,077	153	206
Income taxes paid	185	17
Capitalization of construction-in-progress related to facility lease obligation	96,558	96,671
Non-cash transaction - property and equipment included in accounts payable or accruals	$ 298	$ 738	$ 579