Discontinued Operations, Assets Held for Sale and Asset Sale Transaction - Balance Sheet Components of Discontinued Operations (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets
Current assets held for sale	$ 563	$ 790
Long-term assets
Long-term assets held for sale	458	1,584
Current liabilities
Total current liabilities for sale	113	246
Long-term liabilities
Long-term liabilities held for sale	0	81
CoSense and NFI [Member] | Discontinued Operations, Held-for-sale [Member]
Current assets
Accounts receivable	126	130
Inventory	437	660
Current assets held for sale	563	790
Long-term assets
Property & equipment, net	0	39
Goodwill	0	718
Other intangible assets	458	818
Long-term assets held for sale	458	1,575
Current liabilities
Accounts payable	23	127
Accrued compensation and other current liabilities	90	119
Total current liabilities for sale	113	246
Long-term liabilities
Other long-term liabilities	0	81
Long-term liabilities held for sale	$ 0	$ 81