Summary of Restructuring Activity (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Restructuring Cost And Reserve [Line Items]
Restructuring obligations, December 31, 2013			$ 277
Restructuring costs incurred	796	1,100	796	1,400
Cash payments			(927)
Restructuring obligations, September 30, 2014	146		146
Workforce Reduction [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring costs incurred			796
Cash payments			(779)
Restructuring obligations, September 30, 2014	17		17
Facilities [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring obligations, December 31, 2013			211
Cash payments			(82)
Restructuring obligations, September 30, 2014	129		129
Contract Termination [Member]
Restructuring Cost And Reserve [Line Items]
Restructuring obligations, December 31, 2013			66
Cash payments			$ (66)