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Restructuring - Additional Information (Detail) (USD $)	12 Months Ended			1 Months Ended			16 Months Ended
Restructuring - Additional Information (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Jun. 30, 2014 employee	Mar. 31, 2014 employee	Feb. 28, 2014 employee	Dec. 31, 2014
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 7,760,000us-gaap_RestructuringCharges	$ 3,304,000us-gaap_RestructuringCharges	$ 0us-gaap_RestructuringCharges
Restructuring	1,886,000us-gaap_RestructuringReserveCurrent	610,000us-gaap_RestructuringReserveCurrent					1,886,000us-gaap_RestructuringReserveCurrent
Restructuring Reserve, Noncurrent	60,000us-gaap_RestructuringReserveNoncurrent						60,000us-gaap_RestructuringReserveNoncurrent
2013 Initiatives
Restructuring Cost and Reserve [Line Items]
Reduction in number of employees after restructuring				5	21	41
Restructuring charges	2,900,000	3,300,000
Restructuring costs to date							6,200,000
2014 Initiatives
Restructuring Cost and Reserve [Line Items]
Restructuring charges	4,900,000
Employment Contract Costs \| 2013 Initiatives
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,700,000
Facility Exit Related Costs \| 2013 Initiatives
Restructuring Cost and Reserve [Line Items]
Restructuring charges	1,200,000
Share-based Compensation Costs \| 2014 Initiatives
Restructuring Cost and Reserve [Line Items]
Restructuring charges	$ 1,300,000