Accrued Expenses and Other Current Liabilities (Severance and Restructuring Accruals) (Narrative) (Details) $ in Thousands	1 Months Ended		3 Months Ended	6 Months Ended		12 Months Ended
	Mar. 31, 2017 employee	Nov. 30, 2016 employee	Mar. 31, 2018 USD ($)	Mar. 31, 2018 USD ($) employee	Mar. 31, 2017 USD ($)	Sep. 30, 2018 employee	Sep. 30, 2017 USD ($)
Payables and Accruals [Line Items]
Expense - charged to accrual				$ 679
Employee Severance [Member]
Payables and Accruals [Line Items]
Restructuring costs							$ 400
Expense - charged to accrual				493
Facility Closing [Member]
Payables and Accruals [Line Items]
Expense - charged to accrual				186
Satellite Communications Assembly Operations [Member] | Employee Severance [Member]
Payables and Accruals [Line Items]
Number of positions eliminated | employee		5
Restructuring costs					$ 200
Ivyland, Pennsylvania Location Closure [Member] | Employee Severance [Member]
Payables and Accruals [Line Items]
Restructuring costs							300
Ivyland, Pennsylvania Location Closure [Member] | Facility Closing [Member]
Payables and Accruals [Line Items]
Expense - charged to accrual			$ 200	$ 200
Water Fabrication Lab [Member]
Payables and Accruals [Line Items]
Number of positions eliminated | employee	14
Water Fabrication Lab [Member] | Employee Severance [Member]
Payables and Accruals [Line Items]
Number of positions eliminated | employee	72
Restructuring costs					100
Workforce Reduction [Member] | Employee Severance [Member]
Payables and Accruals [Line Items]
Number of positions eliminated | employee	6
Restructuring costs							$ 400
New Manufacturing Facility in China [Member] | Employee Severance [Member]
Payables and Accruals [Line Items]
Number of positions eliminated | employee	265
Restructuring costs					$ 500
Alignment Towards Chip Devices and Navigation Systems [Member]
Payables and Accruals [Line Items]
Number of positions eliminated | employee				21
Alignment Towards Chip Devices and Navigation Systems [Member] | Employee Severance [Member]
Payables and Accruals [Line Items]
Restructuring costs			$ 400	$ 400
Scenario, Forecast [Member] | Ivyland, Pennsylvania Location Closure [Member] | Employee Severance [Member]
Payables and Accruals [Line Items]
Number of positions eliminated | employee						11