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)
9 Months Ended
Sep. 30, 2018
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]  
Maximum maturity period of cash and cash equivalents 90 days
Maximum maturity period of short-term investments 1 year
Maximum [Member]  
Fair Value Liabilities Measured On Recurring Basis Unobservable Input Reconciliation [Line Items]  
Maturity period of securities 1 year