Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net loss	$ (79,821)	$ (87,305)
Adjustments to reconcile net loss to net cash used in operating activities:
Non-cash interest expense on liability related to sale of future royalties	13,026	9,954
Non-cash equity-related expense	7,480	6,588
Depreciation of property and equipment	1,559	1,310
Interest receivable and amortization on investments	(1,237)	0
(Gain) loss on disposal of equipment	0	(82)
Non-cash interest expense related to debt	412	418
Changes in operating assets and liabilities:
Accounts receivable	(8,044)	(9,976)
Contract assets	13,537	0
Prepaid and other assets	2,026	(2,308)
Accounts payable	(3,230)	1,462
Accrued and other liabilities	(2,109)	(132)
Contract liabilities	(18,750)	0
Deferred revenue	(13,737)	2,383
Net cash used in operating activities	(88,888)	(77,688)
Cash flows from investing activities:
Purchases of investments	(188,428)	(214,457)
Sales and maturities of investments	167,732	119,963
Purchases of property and equipment	(679)	(2,097)
Net cash used in investing activities	(21,375)	(96,591)
Cash flows from financing activities:
Public offerings of common stock, net of issuance costs	0	112,224
Sale of future royalties, net of issuance costs	0	90,621
Issuance of common stock related to sale of future royalties, net of issuance costs	0	7,560
Issuance of long term debt, net of debt discount and issuance costs	9,898	0
Issuance of equity for stock-based awards and warrants, net	2,783	13,320
Net cash provided by financing activities	12,681	223,725
Net increase (decrease) in cash and cash equivalents	(97,582)	49,446
Cash and cash equivalents, beginning of period	125,206	66,874
Cash and cash equivalents, end of period	$ 27,624	$ 116,320