CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017		Mar. 31, 2016
Cash flows from operating activities:
Net income (loss)	$ (187,083)		$ 24,047
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation and amortization	15,027		11,058
Stock-based compensation	30,613		20,769
Expense related to senior note conversions	54,130
Other, net	71		178
Unrealized loss on long term investment	5,814		2,950
Change in fair value of acquisition-related contingent consideration	7,356
Changes in operating assets and liabilities:
Accounts receivable	(96,217)		13,170
Prepaid expenses and other assets	(25,094)		(3,667)
Inventory	790		752
Accounts payable	10,728		1,814
Accrued and other liabilities	10,227		29,679
Deferred revenue-collaborative agreements			(3,215)
Net cash provided by (used in) operating activities	(173,638)		97,535
Cash flows from investing activities:
Purchase of long term investments	(123,891)
Capital expenditures	(20,967)		(5,562)
Purchases of marketable securities	(106,271)		(16,795)
Sale and maturities of marketable securities	112,310		51,114
Net cash provided by (used in) investing activities	(138,819)		28,757
Cash flows from financing activities:
Restricted investments, net	(16)		110
Proceeds from issuance of common stock under stock plans	33,736		10,219
Cash paid in connection with senior note conversions	(8,097)
Direct financing arrangements repayments			(445)
Payment of contingent consideration	(3,679)
Net cash provided by financing activities	21,944		9,884
Effect of exchange rates on cash and cash equivalents	(7)
Net increase (decrease) in cash and cash equivalents	(290,520)		136,176
Cash and cash equivalents at beginning of period	652,343	[1]	521,439
Cash and cash equivalents at end of period	361,823		657,615
Supplemental Schedule of Cash Flow Information
Interest paid			846
Income taxes paid	2,244		14
Unpaid purchases of property and equipment	9,139
0.375% Convertible Senior Notes due 2018
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Expense related to senior note conversions	1,500
Supplemental Schedule of Cash Flow Information
Reclassification to common stock and additional paid in capital in connection with conversions or exchange of convertible senior notes	334,162
1.25% Convertible Senior Notes due 2020
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Expense related to senior note conversions	5,100
Supplemental Schedule of Cash Flow Information
Reclassification to common stock and additional paid in capital in connection with conversions or exchange of convertible senior notes	$ 328,382		$ 4

[1] The condensed consolidated balance sheet at December 31, 2016 has been derived from the audited financial statements at that date.