FINANCING ARRANGEMENTS - Capital Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Capital Leases
Total cost of the leased equipment	$ 1,574			$ 1,524
Current maturities of capital leases	325			$ 295	[1]
Interest expense related to the leased assets	26	$ 0
Depreciation expense related to the leased assets	39	$ 0
Future minimum lease payments under non-cancelable capital leases
Remainder of 2018	286
2019	394
2020	394
2021	394
2022	255
Total noncancelable future lease commitments	1,723
Less interest	(204)
Present value obligations under capital leases	$ 1,519
Forecast
Future minimum lease payments under non-cancelable capital leases
Total noncancelable future lease commitments			$ 34

[1] The balance sheet at December 31, 2017 has been derived from the audited financial statements at that date