Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Additional Information (Detail)

v3.10.0.1
Fair Value Measurements - Additional Information (Detail) - USD ($)
9 Months Ended
Sep. 30, 2018
Dec. 31, 2017
Fair value of assets transfers in or out, level 1 to level 2 $ 0  
Fair value of assets transfers in or out, level 2 to level 1 0  
Fair value, asset transfers into Level 3 0  
Fair value, asset transfers out of Level 3 0  
Fair Value Measurements, Recurring    
Assets at fair value on recurring basis 0 $ 0
Liabilities at fair value on recurring basis $ 0 $ 0