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

Collaborative Arrangements - BioAxone Biosciences, Inc. (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2014	Dec. 31, 2017
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Contingent liabilities		$ 0		$ 0
BioAxone Biosciences, Inc
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Up-front payment	$ 10,000,000	$ 10,000,000	$ 10,000,000