Basic and Diluted Net Loss Per Common Share - Computation of Basic and Diluted Net Loss Per Common Share (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Numerator:
Net loss	$ (36,424)	$ (14,484)
Denominator
Weighted average common shares, Denominator for basic calculation	31,338	26,826
Weighted average common shares, Denominator for diluted calculation	31,338	26,826
Net loss per share:
Basic	$ (1.16)	$ (0.54)
Diluted	$ (1.16)	$ (0.54)