Commitments and Contingencies (Detail) - USD ($) $ in Thousands	1 Months Ended
	Oct. 31, 2001	Sep. 30, 2017	Mar. 31, 2017	Dec. 31, 2016
Commitment Contingencies And Guarantees [Line Items]
Accrued expenses		$ 2,495		$ 2,223
Other long-term liabilities		3,504		$ 3,630
Annual payments	$ 650
Employee Severance
Commitment Contingencies And Guarantees [Line Items]
Maximum severance payments		3,000
Letter of credit
Commitment Contingencies And Guarantees [Line Items]
Letter of credit under the credit facility		6,300
Accrued expenses and other current liabilities
Commitment Contingencies And Guarantees [Line Items]
Liability to former chairman and chief executive officer, current		800
Other long-term liabilities
Commitment Contingencies And Guarantees [Line Items]
Liability to former chairman and chief executive officer, non-current		1,800
Clawback Liability
Commitment Contingencies And Guarantees [Line Items]
Other long-term liabilities		$ 300
Company's ownership in the funds		19.00%
Clawback Liability Paid			$ 1,000
Private equity funds
Commitment Contingencies And Guarantees [Line Items]
Company outstanding guarantees		$ 3,800