Income Taxes (Details 2) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Deferred tax assets:
Net operating loss carryforwards	$ 84,893	$ 57,169
Stock-based compensation	1,691	1,163
Property, plant and equipment	7,838	18,927
Other	1,239	1,555
Deferred tax assets, gross	95,661	78,814
Less: Valuation allowance	(92,795)	(60,921)
Total deferred tax assets	2,866	17,893
Deferred tax liabilities:
Property, plant and equipment	(2,388)	(64,232)
Other	(478)	(733)
Total deferred tax liabilities	(2,866)	(64,965)
Net deferred tax asset (liability)	0	(47,072)
Mexico
Deferred tax assets:
Net operating loss carryforwards		16,300
Velardena Operations
Deferred tax liabilities:
Property, plant and equipment		$ (63,700)