Boeing Insourcing Agreement (Details Textual) - USD ($)			3 Months Ended		9 Months Ended		12 Months Ended
	Jan. 03, 2017	Nov. 28, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2017
Boeing Insourcing Agreement [Line Items]
Gain from derecognition of purchase accounting liability			$ 0	$ 0	$ 14,189,000	$ 0
Assembled Workforce [Member]
Boeing Insourcing Agreement [Line Items]
Definite-lived intangible asset	7 years
Insourcing Agreement [Member] | Boeing [Member]
Boeing Insourcing Agreement [Line Items]
Agreed costs associated with hiring of employees		$ 5,500,000
Agreed costs paid associated with hiring of employees							$ 2,750,000
Development Services Agreement [Member] | Boeing [Member]
Boeing Insourcing Agreement [Line Items]
Annual commitment amount	$ 6,000,000
Annual commitment term	2021
Scenario, Forecast [Member] | Insourcing Agreement [Member] | Boeing [Member]
Boeing Insourcing Agreement [Line Items]
Agreed costs payable at year end associated with hiring of employees								$ 2,750,000