CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating activities:
Net income (loss)	$ (119,772)	$ 18,931
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation	3,715	3,406
Amortization of patents	774	648
Amortization of licenses	1	937
Amortization of premium on investments, net	3,793	3,377
Amortization of debt issuance costs	601	555
Amortization of long-term financing liability for leased facility	3,345	3,327
Stock-based compensation expense	39,364	26,910
Non-cash losses related to patents, licensing and property, plant and equipment	464	166
Changes in operating assets and liabilities:
Contracts receivable	10,610	639
Inventories	(769)	(492)
Other current and long-term assets	(2,576)	(14,629)
Accounts payable	(12,436)	(8,197)
Accrued compensation	(8,624)	(4,387)
Deferred rent	101	167
Accrued liabilities	(9,133)	(6,698)
Deferred contract revenue	(30,719)	(13,097)
Net cash provided by (used in) operating activities	(109,552)	22,381
Investing activities:
Purchases of short-term investments	(81,814)	(240,570)
Proceeds from the sale of short-term investments	180,158	187,522
Purchases of property, plant and equipment	(3,263)	(3,940)
Acquisition of licenses and other assets, net	(2,195)	(1,749)
Net cash used in investing activities	92,886	(58,737)
Financing activities:
Proceeds from equity awards	4,120	18,035
Principal payments on debt and capital lease obligations	(3,717)	(5,190)
Net cash provided by financing activities	403	12,845
Net decrease in cash and cash equivalents	(16,263)	(23,511)
Cash and cash equivalents at beginning of period	128,797	142,998
Cash and cash equivalents at end of period	112,534	119,487
Supplemental disclosures of cash flow information:
Interest paid	3,414	3,377
Supplemental disclosures of non-cash investing and financing activities:
Amounts accrued for capital and patent expenditures	1,662	1,166
2 3/4 Percent Convertible Senior Notes [Member]
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Amortization of convertible senior notes discount	1,254	1,146
1 Percent Convertible Senior Notes [Member]
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Amortization of convertible senior notes discount	$ 10,455	$ 9,672