Quarterly report pursuant to Section 13 or 15(d)

Recent Accounting Pronouncements and Developments - Additional Information (Detail)

v3.8.0.1
Recent Accounting Pronouncements and Developments - Additional Information (Detail) - Adjustments for New Accounting Principle, Early Adoption [Member] - USD ($)
$ in Millions
Jan. 01, 2017
Sep. 30, 2017
Retained Deficit [Member] | ASU 2016-09 [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Impact of reclassification adjustment due to adoption of new accounting pronouncement $ 0.2  
Deferred Tax Asset [Member] | ASU 2016-09 [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Impact of reclassification adjustment due to adoption of new accounting pronouncement $ 0.2  
Deferred Tax Asset Non Current [Member] | ASU 2015-17 [Member]    
New Accounting Pronouncements or Change in Accounting Principle [Line Items]    
Impact of reclassification adjustment due to adoption of new accounting pronouncement   $ 2.7