Commitments and Contingencies - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loss Contingencies [Line Items]
Rent expense	$ 3.8	$ 2.5	$ 1.6
Other Current and Long-term Liabilities
Loss Contingencies [Line Items]
Deferred rent	$ 1.0	$ 0.5

For a classified balance sheet, the cumulative difference between the rental income or payments required by a lease agreement and the rental income or expense recognized on a straight-line basis, or other systematic and rational basis more representative of the time pattern in which use or benefit is granted or derived from the leased property, expected to be recognized in income or expense, by the lessor or lessee, respectively, within one year (or one operating cycle, if longer) of the balance sheet date. Such receivable is reduced by allowances attributable to, for instance, credit risk associated with a lessee.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.8)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 25
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77902458&loc=d3e39927-112707

Name:	us-gaap_DeferredRentAssetNetCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant