ACCRUED LIABILITIES (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
ACCRUED LIABILITIES
Accrued payroll and benefits		$ 3,277	$ 3,316
Accrued property taxes		218	86
Income taxes payable		292	198
Accrued professional fees		214	126
Accrued warranty liability	457	736	1,198	370
Accrued regulatory settlement		1,012	2,066
Accrued environmental reserve		513	513
Accrued self-insurance reserve		1,362	1,411
Accrued other		251	639
Total accrued liabilities		7,875	9,553
Current portion of environmental settlement recorded	500
Estimated SEC Inquiry settlement recorded		$ 512