Restatement of Previously Issued Unaudited Interim Condensed Consolidated Financial Statements (Details 2) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Accounts receivable, net	$ 16,081	$ 12,742
Total current assets	49,537	59,131	$ 92,156
Property, plant and equipment, net	83,290	68,355
Total assets	186,779	184,585	193,532
Accounts payable	8,771	10,595
Total current liabilities	18,040	18,696	18,875
Convertible 4.75% Senior Notes, net of debt discount and debt issuance costs (face of $75,090, as of June 30, 2018)	55,369	0
Total liabilities	148,067	139,832	135,124
Additional paid-in capital	118,524	106,312
Accumulated deficit	(78,015)	(60,094)
Total stockholders’ equity	38,712	44,753
Total liabilities and stockholders' equity	186,779	184,585	193,532
As Previously Reported
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Accounts receivable, net	16,232
Total current assets	49,688	64,532	95,009
Property, plant and equipment, net	83,027
Total assets	186,667	189,986	196,385
Accounts payable	8,654
Total current liabilities	17,923	24,097	21,728
Convertible 4.75% Senior Notes, net of debt discount and debt issuance costs (face of $75,090, as of June 30, 2018)	54,963
Total liabilities	147,544	145,233	137,977
Additional paid-in capital	126,532
Accumulated deficit	(85,612)
Total stockholders’ equity	39,123
Total liabilities and stockholders' equity	186,667	189,986	196,385
Adjustment
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Accounts receivable, net	(151)
Total current assets	(151)	5,401	2,853
Property, plant and equipment, net	263
Total assets	112	5,401	2,853
Accounts payable	117
Total current liabilities	117	5,401	2,853
Convertible 4.75% Senior Notes, net of debt discount and debt issuance costs (face of $75,090, as of June 30, 2018)	406
Total liabilities	523	5,401	2,853
Additional paid-in capital	(8,008)
Accumulated deficit	7,597
Total stockholders’ equity	(411)
Total liabilities and stockholders' equity	$ 112	$ 5,401	$ 2,853