Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities
Net loss	$ (50,074)	$ (34,657)	$ (21,911)
Adjustments to reconcile net loss to net cash provided by and (used in) operating activities:
Depreciation and amortization	2,370	3,184	1,290
Non-cash interest expense	392	451	0
Gain on sale of IgDraSol	(69,274)	0	0
Stock-based compensation	6,972	3,940	1,789
Acquired in-process research and development	12,000	209	1,905
Provision for doubtful accounts	5	33	0
Loss on derivative liability	3,360	0	0
Loss on equity investments	4,041	0	0
Deferred tax provision	33,337	(1,702)	0
Changes in operating assets and liabilities; net of dispositions:
Grants and other receivables	(176)	(371)	117
Prepaid expenses and other	(1,052)	(979)	(441)
Income tax receivable	(1,715)	0	0
Accounts payable	(2,713)	(497)	878
Deferred revenue	9,876	0	0
Accrued expenses and other liabilities	10,582	1,625	(116)
Net cash used for operating activities	(42,069)	(28,764)	(16,489)
Investing activities
Purchases of property and equipment	(3,707)	(591)	(420)
Purchases of intangible assets	0	0	(511)
Cash received in connection with mergers	0	0	428
Investments in common stock	(11,500)	(10,000)	0
Net cash provided by (used in) investing activities	12,552	(10,591)	(503)
Financing activities
Net borrowings under loan and security agreement	0	7,500	6,850
Proceeds from issuance of common stock, net of issuance costs and repurchases	0	71,786	37,701
Net principal payments under loan and security agreement	(3,095)	0	0
Net payments of deferred compensation	(2,000)	0	(1,000)
Sale of a noncontrolling interest	49	0	0
Proceeds from exercise of stock options	1,699	304	17
Net cash (used in) provided by financing activities	(3,347)	79,590	43,568
Net change in cash and cash equivalents	(32,864)	40,235	26,576
Cash and cash equivalents at beginning of period	71,902	31,667	5,091
Cash and cash equivalents at end of period	39,038	71,902	31,667
Cash paid during the period for:
Income taxes	3,001	6	1
Interest paid	1,574	1,544	0
Supplemental disclosures of non-cash investing and financing activities:
Change in unrealized gains (losses) on marketable securities	73,579	0	0
Common stock received in exchange for license	(100,000)	0	0
Contributions to equity method investments made on Company's behalf	(60,000)	0	0
Property and equipment costs incurred but not paid	2,396	0	0
IgDraSol, Inc. [Member]
Adjustments to reconcile net loss to net cash provided by and (used in) operating activities:
Gain on sale of IgDraSol	(69,274)	0	0
Investing activities
Proceeds from sale of IgDraSol	27,759	0	0
Supplemental disclosures of non-cash investing and financing activities:
Issuance of 1,306,272 shares to former stockholders of IgDraSol	$ 0	$ 0	$ 0