Quarterly report pursuant to Section 13 or 15(d)

Commitments and Contingencies - Additional Information (Detail)

v3.7.0.1
Commitments and Contingencies - Additional Information (Detail)
$ in Millions
3 Months Ended 6 Months Ended
Jun. 30, 2017
USD ($)
lease
Jun. 30, 2016
USD ($)
Jun. 30, 2017
USD ($)
lease
Jun. 30, 2016
USD ($)
Other Commitments [Line Items]        
Number of leases | lease 4   4  
Expenses incurred for the properties listed $ 0.1 $ 0.1 $ 0.2 $ 0.2
Line of credit        
Other Commitments [Line Items]        
Letters of credit, outstanding $ 1.0   $ 1.0