Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130543-203045

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=118956577&loc=SL49130545-203045

Name:	us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Revenue (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Revenue
Revenue accounted for under Topic 606	$ 487	$ 525	$ 1,276	$ 2,228
Product revenue, gross	100		400
Collaboration revenue
Revenue
Revenue accounted for under Topic 606	7		152	1,000
Collaboration revenue - Upfront payment
Revenue
Revenue accounted for under Topic 606	(48)		108
Product revenue, gross	149		398
Collaboration revenue - Variable consideration
Revenue
Revenue accounted for under Topic 606	7		152	1,000
Research premium
Revenue
Revenue accounted for under Topic 606	301	351	591	744
Government grants
Revenue
Revenue accounted for under Topic 606	$ 227	$ 174	$ 425	$ 484