Quarterly report pursuant to Section 13 or 15(d)

Commitments and Contingencies - Additional Information (Detail)

v3.10.0.1
Commitments and Contingencies - Additional Information (Detail)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2018
USD ($)
lease
Sep. 30, 2017
USD ($)
Sep. 30, 2018
USD ($)
lease
Sep. 30, 2017
USD ($)
Other Commitments [Line Items]        
Number of leases | lease 4   4  
Expenses incurred for the properties listed $ 0.1 $ 0.1 $ 0.4 $ 0.4
Line of credit        
Other Commitments [Line Items]        
Letters of credit, outstanding $ 1.2   $ 1.2