Description of Business and Basis of Presentation (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Schedule of computation of basic and diluted net income (loss) per share
Net income	$ (3,292)	$ 6,027	$ (4,154)	$ 9,154
Effect of assumed conversion of convertible debentures
Weighted-average common shares outstanding	29,284	28,884	29,146	28,857
Weighted-average common shares outstanding, assuming dilution	29,284	28,940	29,146	28,883
Net income per share
Basic	$ (0.11)	$ 0.21	$ (0.14)	$ 0.32
Diluted	$ (0.11)	$ 0.21	$ (0.14)	$ 0.32
Stock Options
Effect of assumed conversion of convertible debentures
Effect of potentially dilutive securities	0	35	0	17
Restricted Stock [Member]
Effect of assumed conversion of convertible debentures
Effect of potentially dilutive securities	0	1	0	4
Restricted Stock Unit
Effect of assumed conversion of convertible debentures
Effect of potentially dilutive securities	0	20	0	5