Net Loss Per Share - Computation of Basic and Diluted Earnings per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Basic and diluted:
Net loss	$ (10,593)	$ (2,906)
Basic:
Weighted-average common shares outstanding, basic (in shares)	42,039	33,715
Dilutive effect of stock options	0	0
Diluted:
Weighted-average common shares outstanding, diluted (in shares)	42,039	33,715
Net loss per share:
Basic (in dollars per share)	$ (0.25)	$ (0.09)
Diluted (in dollars per share)	$ (0.25)	$ (0.09)