Collaborative Arrangements and Revenue Recognition - Summary of Revenues Disaggregated by Recognition at Point in Time and Over Time (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Point in Time
Disaggregation of Revenue [Line Items]
Revenues	$ 3,791	$ 19,378
Point in Time | Other contract revenue
Disaggregation of Revenue [Line Items]
Revenues	0	251
Point in Time | Healios | License fee revenue
Disaggregation of Revenue [Line Items]
Revenues	1,624	17,682
Point in Time | Healios | Product supply revenue
Disaggregation of Revenue [Line Items]
Revenues	2,167	1,445
Point in Time | Healios | Service revenue
Disaggregation of Revenue [Line Items]
Revenues	0	0
Over Time
Disaggregation of Revenue [Line Items]
Revenues	1,726	3,149
Over Time | Other contract revenue
Disaggregation of Revenue [Line Items]
Revenues	0	0
Over Time | Healios | License fee revenue
Disaggregation of Revenue [Line Items]
Revenues	0	0
Over Time | Healios | Product supply revenue
Disaggregation of Revenue [Line Items]
Revenues	0	0
Over Time | Healios | Service revenue
Disaggregation of Revenue [Line Items]
Revenues	$ 1,726	$ 3,149