Summary of Significant Accounting Policies - Summary of Product Revenue by Geographical Locations of Customers (Detail) - Product - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation Of Revenue [Line Items]
Total product revenue	$ 18,209	$ 15,420	$ 35,713	$ 28,984
North America
Disaggregation Of Revenue [Line Items]
Total product revenue	5,158	3,149	9,709	5,536
Europe, Middle East and Africa
Disaggregation Of Revenue [Line Items]
Total product revenue	12,748	12,018	25,400	23,024
Other
Disaggregation Of Revenue [Line Items]
Total product revenue	$ 303	$ 253	$ 604	$ 424

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

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