SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Change in Accounting (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Unbilled Contracts Receivable	$ 55,490	$ 38,951	$ 37,785
Inventories, net	26,342	24,045	24,337
Prepaid Expense, Current	3,456	1,863	2,266
Accrued Liabilities, Current	16,190	17,911	17,862
Deferred Revenue, Current	3,465	7,833	6,090
Deferred Tax Liabilities, Net, Noncurrent	15,735	19,042	19,367
Accumulated deficit	(133,208)	(116,429)	(115,433)
Calculated under Revenue Guidance in Effect before Topic 606 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Unbilled Contracts Receivable	55,188		37,785
Inventories, net	26,610		24,337
Prepaid Expense, Current			2,266
Accrued Liabilities, Current	15,737		17,862
Deferred Revenue, Current	3,016		6,090
Deferred Tax Liabilities, Net, Noncurrent	16,085		19,367
Accumulated deficit	$ (132,690)		$ (115,433)
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Unbilled Contracts Receivable		1,166
Inventories, net		(292)
Prepaid Expense, Current		(403)
Accrued Liabilities, Current		49
Deferred Revenue, Current		1,743
Deferred Tax Liabilities, Net, Noncurrent		(325)
Accumulated deficit		$ (996)