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.

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

Revenue Recognition - performance of obligations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Performance of obligations
Amounts included in the contract liability in the beginning of the period			$ 70	$ 45
Out-licensing agreements
Performance of obligations
Amounts included in the contract liability in the beginning of the period	$ 23	$ 15