Stock-based Compensation and Equity Grants - Stock-based Compensation Expense (Details) - USD ($) $ in Thousands		12 Months Ended
	Nov. 09, 2018	Sep. 30, 2018	Sep. 30, 2017
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total compensation expense		$ 1,375	$ 662
Period for recognition of related compensation expense		4 years 3 months
Selling, General and Administrative Expenses | DLH employees
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total compensation expense		$ 266	166
Total unrecognized expense		876	299
Selling, General and Administrative Expenses | Non-employee directors
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total compensation expense		$ 1,109	$ 496
Selling, General and Administrative Expenses | Non-employee directors | Common Stock | Subsequent Event
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Number of cliff-vested shares of common stock issued (in shares)	101,667