Contingencies - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Jul. 31, 2018
Commitments And Contingencies Disclosure [Abstract]
Accrued other long-term liabilities	$ 3.9
Estimated sales and marketing expense	$ 0.3	$ 0.3
Freezing amount in cash resulted from court pending legal action issued			$ 2.5

Amount of expenses incurred but not yet paid classified as other, due after one year or the normal operating cycle, if longer.

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 210.5-02.24)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Name:	us-gaap_OtherAccruedLiabilitiesNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant