Discontinued Operations - Reconciliation of discontinued operations presented in condensed consolidated balance sheets (Details 1) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Accounts receivable, net	$ 325	$ 394
Costs in excess of billings on uncompleted contracts	62	62
Inventory, net	69	63
Other current assets	624	723
Total major classes of current assets of the discontinued operations	1,080	1,242
Noncurrent assets:
Other noncurrent assets	574	579
Total noncurrent assets of discontinued operations	574	579
Total assets of the discontinued operations in the balance sheet	1,654	1,821
Current liabilities:
Accounts payable	270	270
Accrued liabilities	33	33
Deferred revenue and other current liabilities	486	418
Total current liabilities of discontinued operations	789	721
Noncurrent liabilities:
Other liabilities	729	745
Total major classes of noncurrent liabilities of the discontinued operations	729	745
Total liabilities of the discontinued operations in the balance sheet	$ 1,518	$ 1,466