Significant Accounting Policies Significant Accounting Policies (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) Customer Markets	Mar. 31, 2017 USD ($)	Jul. 01, 2018 USD ($)	Jun. 30, 2018 USD ($)	Jan. 03, 2018 $ / shares shares	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of primary end markets | Markets	2
Backlog	$ 32,300
Common stock purchase limit (in shares) | shares					6,006,667
Price per share (in usd per share) | $ / shares					$ 1.00
Restricted cash	4,000					$ 0	$ 0
Deferred Income Tax Expense (Benefit)	$ 306	$ 195
Scenario, Forecast [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Restricted cash			$ 6,000	$ 4,000
Hardware Solutions [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of customers | Customer	1