Quarterly Financial Data (Unaudited) - Summary of Quarterly Financial Data (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2012		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Quarterly Financial Information Disclosure [Abstract]
Revenue	$ 53,065		$ 50,196		$ 51,020		$ 50,443		$ 52,743		$ 46,839		$ 48,235		$ 48,461		$ 204,724	$ 196,278	$ 197,711
Gross profit	35,255		24,232		32,093		32,742		32,120		29,633		30,196		31,819		124,322	123,768	116,930
Total operating expenses	91,257		37,406		34,992		34,100		36,108		31,606		33,947		31,944		197,755	133,605	141,446
Net loss	$ (60,407)		$ (14,510)		$ (4,661)		$ (2,649)		$ (5,355)		$ (2,469)		$ (6,374)		$ (1,261)		$ (82,227)	$ (15,459)	$ (22,181)
Basic and diluted net loss per share (in dollars per share)	$ (0.62)	[1]	$ (0.15)	[1]	$ (0.05)	[1]	$ (0.03)	[1]	$ (0.06)	[1]	$ (0.03)	[1]	$ (0.07)	[1]	$ (0.01)	[1]	$ (0.85)	$ (0.17)	$ (0.25)

[1] Basic and diluted net loss per share is computed independently for each of the quarters presented. Therefore, the sum of the quarterly per share amounts will not necessarily equal the total for the year.