Employee Benefit Plans - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Accrued severance and restructuring liability	$ 1,600,000	$ 1,500,000	$ 2,600,000
Severance benefits, annual severance pay awarded, period	14 days
Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract]
Percent of employee's contribution matched half by employer	50.00%
Defined contribution plan, employee's gross salary, percent	5.00%
Employer contributions vesting percentage for year two	66.00%
Employer contributions vesting percentage for year three	100.00%
Defined contribution plan, matching contribution	1,100,000	1,100,000	1,100,000
Defined contribution plan, vested working hours	1000 hours
Employer contributions vesting percentage for year one	33.00%
Defined Contribution Plan, Maximum Annual Contribution Per Employer, Amount	$ 2,500
Employer contributions vesting period	3 years
Employees minimum employment period to participate in plan	30 days
Minimum number of hours worked by employees to cover under the plan	20 hours
Minimum [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Severance benefits, severance pay period	14 days
Maximum [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Severance benefits, severance pay period	182 days