Collaborative Arrangements and Revenue Recognition - Additional Information (Details)	12 Months Ended
Dec. 31, 2019 Milestone
Regulatory and sales milestones \| Healios
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Number of future milestones achieved	2

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_CollaborativeArrangementsAndNoncollaborativeArrangementTransactionsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration