Segment Reporting - Schedule of Segment Information (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Total net revenues	$ 1,326		$ 320		$ 2,791	$ 323
Total net loss	(22,792)	$ (25,573)	(14,000)	$ (11,777)	(48,365)	(25,777)
Regenerative Medicine [Member]
Total net revenues	504		189		801	192
Total net loss	(23,014)		(13,843)		(48,782)	(25,620)
Contract Services [Member]
Total net revenues	822		131		1,990	131
Total net loss	$ 222		$ (157)		$ 417	$ (157)