Basis of Presentation and Summary of Significant Accounting Policies - Concentrations of Credit Risk (Details)	9 Months Ended	12 Months Ended
	Jun. 30, 2018	Sep. 30, 2017
Cash and Cash Equivalents and Restricted Cash | US Treasuries and FDIC Insured
Concentration Risk [Line Items]
Concentration risk, percentage	60.00%
Cash and Cash Equivalents and Restricted Cash | US Treasuries and FDIC Insured
Concentration Risk [Line Items]
Concentration risk, percentage		45.00%
Customer One | Accounts Receivable | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	23.00%	24.00%
Customer Two | Accounts Receivable | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	14.00%	11.00%
Equipment Sales
Concentration Risk [Line Items]
Percentage of sales affected by revenue recognition adoption		5.00%