Summary of Significant Accounting Policies - Additional Information (Details) $ in Millions	6 Months Ended
Jun. 30, 2018 USD ($)
Other income (expense) net, including interest income
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Realized foreign currency translation gain	$ 0.3
Supply Agreement \| Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred revenue, average initial contract term	1 year
Supply Agreement \| Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred revenue, average initial contract term	5 years

Amount before tax of foreign currency transaction realized gain (loss) recognized in the income statement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=109240200&loc=d3e30690-110894

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6450222&loc=d3e30840-110895

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 830
-SubTopic 20
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109240200&loc=d3e30700-110894

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