Summary of Major Types of Costs, Cumulative Costs Incurred and Total Cost Expected Associated With Restructuring Activities (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 90	$ 0	$ 175	$ 0
Cumulative Costs Incurred To Date	14,907		14,907
Total Expected Plan Costs	15,032		15,032
Severance and related employee benefits
Restructuring Cost and Reserve [Line Items]
Cumulative Costs Incurred To Date	13,162		13,162
Total Expected Plan Costs	13,162		13,162
Contract termination costs
Restructuring Cost and Reserve [Line Items]
Cumulative Costs Incurred To Date	1,159		1,159
Total Expected Plan Costs	1,159		1,159
Other costs
Restructuring Cost and Reserve [Line Items]
Cumulative Costs Incurred To Date	586		586
Total Expected Plan Costs	711		711
Operating expenses
Restructuring Cost and Reserve [Line Items]
Restructuring costs	90	0	175	0
Operating expenses \| Severance and related employee benefits
Restructuring Cost and Reserve [Line Items]
Restructuring costs	0	0	0	0
Operating expenses \| Contract termination costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs	0	0	0	0
Operating expenses \| Other costs
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 90	$ 0	$ 175	$ 0