Fair Value Measurements - Assets Categorized on Basis of Various Levels (Detail) $ in Thousands	Dec. 31, 2016 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market fund deposits	$ 321
Mutual fund investments	8
Total	329
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market fund deposits	321
Mutual fund investments	8
Total	$ 329