Carrying amount as of the balance sheet date of amounts due under the terms of governmental, corporate, or foundation grants.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.8)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Name:	us-gaap_GrantsReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

The Business - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017	Feb. 28, 2017
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Grants awarded	$ 8.1		$ 12.2
CD34 cell technology
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Grants awarded		$ 1.9