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Revenue and Vendor Concentrations - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016	Sep. 30, 2016
Revenue, Major Customer [Line Items]
Revenue	$ 11,419	$ 8,522	$ 20,688	$ 15,926
Accounts receivable, net	5,104		$ 5,104		$ 4,949
Customer Concentration Risk \| Sales Revenue Net
Revenue, Major Customer [Line Items]
Total revenue, percentage (as a percent)			23.00%
Customer Concentration Risk \| Accounts Receivable
Revenue, Major Customer [Line Items]
Accounts receivable, net	1,400	100	$ 1,400	100
Customer Concentration Risk \| Two Customers \| Sales Revenue Net
Revenue, Major Customer [Line Items]
Revenue	$ 2,900	$ 2,100		$ 3,900
Customer Concentration Risk \| Customer One \| Sales Revenue Net
Revenue, Major Customer [Line Items]
Total revenue, percentage (as a percent)	14.00%	15.00%		13.00%
Customer Concentration Risk \| Customer Two \| Sales Revenue Net
Revenue, Major Customer [Line Items]
Total revenue, percentage (as a percent)	12.00%	11.00%		12.00%
Customer Concentration Risk \| One Customer \| Sales Revenue Net
Revenue, Major Customer [Line Items]
Revenue			$ 4,800
Geographic Concentration Risk \| Sales Revenue Net
Revenue, Major Customer [Line Items]
Total revenue, percentage (as a percent)	14.00%	10.00%	12.00%	10.00%