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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130543-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130539-203045

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130545-203045

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

Revenue Recognition - Disaggregated Revenues by Timing of Transfer of Goods or Services (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disaggregation of Revenue [Line Items]
Disaggregated Revenue	$ 4,011	$ 3,787	$ 10,655	$ 8,915
Product Revenue, net
Disaggregation of Revenue [Line Items]
Disaggregated Revenue	2,265		2,871
Collaboration and License Revenue
Disaggregation of Revenue [Line Items]
Disaggregated Revenue	1,746		7,784
Transferred at a point in time
Disaggregation of Revenue [Line Items]
Disaggregated Revenue	2,265		2,871
Transferred at a point in time \| Product Revenue, net
Disaggregation of Revenue [Line Items]
Disaggregated Revenue	2,265		2,871
Transferred over time
Disaggregation of Revenue [Line Items]
Disaggregated Revenue	1,746		7,784
Transferred over time \| Collaboration and License Revenue
Disaggregation of Revenue [Line Items]
Disaggregated Revenue	$ 1,746		$ 7,784