Segments - Reconciliation of Revenues from Reportable Segments to Consolidated Revenues (Details) - USD ($) $ in Thousands	3 Months Ended										12 Months Ended
	Dec. 31, 2019	[1]	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	[2]	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues	$ 17,002		$ 18,299	$ 32,836	$ 22,585	$ 41,192		$ 30,055	$ 42,771	$ 37,160
Revenues											$ 90,722	$ 151,178	$ 219,463
Other revenues, including from other operating segments
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues											18,602	30,914	59,861
Elimination of intersegment revenues
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues											(15,524)	(2,570)	(2,056)
Total segment revenues from reportable segments
Segment Reporting, Asset Reconciling Item [Line Items]
Revenues											$ 87,644	$ 122,834	$ 161,658

[1] During the fourth quarter of 2019, the Company recorded a goodwill impairment charge related to the Trans Ova reporting unit (Note 11) as well as impairment charges on certain assets held for sale (Note 3).

[2] During the fourth quarter of 2018, the Company reacquired certain in-process research and development from ZIOPHARM, Ares Trading, and Intrexon T1D Partners, all of which were immediately expensed (Notes 5 and 6). The Company also recorded a loss on abandonment of certain of its intangible assets (Note 11). The Company also recognized the remaining balance of deferred revenue associated with Histogenics and Synthetic Biologics upon the mutual termination of the ECCs with these entities (Note 18).