Fair Value Measurements - Narrative (Detail) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	May 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Marketable securities, current	$ 0	$ 37,955
Revolving Credit Facility [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Line of Credit Facility, Repayment Feature, Noncurrent		5,100	$ 4,500
Amended Credit Facility [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt Instrument, Debt Covenants, Cash and Cash Equivalent Threshold		$ 50,000		$ 50,000