Basis of Presentation and Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 31, 2017	Jun. 30, 2017
ASU 2016-09 [Member]
Summary Of Significant Accounting Policy [Line Items]
Decrease in accumulated deficit due to the recognition of excess tax benefit after valuation allowance	$ 1.8	$ 1.8

Amount of the cumulative effect on retained earnings net of related income tax effect.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 250
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=64853466&loc=d3e22663-107794

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration