Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities
Net loss	$ (99,720)	$ (74,082)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash interest expense	6,131	6,393
Depreciation and amortization	4,320	2,811
Stock-based compensation	12,027	9,941
Changes in operating assets and liabilities
Purchased premiums and interest on available-for-sale securities		432
Accounts receivable	1,262	4,130
Accounts payable, accrued expenses and other	335	(2,077)
Deferred revenues	(25,922)	49,526
Other assets and liabilities, net	(481)	(197)
Net cash used in operating activities	(102,048)	(3,123)
Cash flows from investing activities
Purchases of available-for-sale securities		(70,934)
Proceeds from maturities of available-for-sale securities	81,899	106,733
Purchases of property and equipment	(8,127)	(4,714)
Net cash provided by investing activities	73,772	31,085
Cash flows from financing activities
Proceeds from exercise of common stock options and warrants	8,295	6,581
Proceeds from at the market offering, net of issuance costs	38,560
Proceeds from issuance of preferred stock of Silver Creek Pharmaceuticals, Inc.	2,083
Proceeds from convertible notes issued by Silver Creek Pharmaceuticals, Inc., net of issuance costs		700
Payments of dividends on Series B convertible preferred stock		(7)
Other financing activities, net		1
Net cash provided by financing activities	48,938	7,275
Net increase in cash and cash equivalents	20,662	35,237
Cash and cash equivalents, beginning of period	35,688	65,086
Cash and cash equivalents, end of period	56,350	100,323
Non-cash investing and financing activities
Disposal of fully depreciated assets	106	1,598
Property and equipment in accounts payable and accrued expenses	1,800	653
Receivables related to stock option exercises	87	841
Issuance of derivative liability		88
Supplemental disclosure of cash flows
Cash paid for interest	$ 8,837	$ 8,806