Basis of Presentation and Significant Accounting Policies Basis of Presentation and Significant Accounting Policies - Recently Adopted Accounting Pronouncements (Details) - USD ($) $ in Thousands	Oct. 01, 2018	Mar. 31, 2019	Sep. 30, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit	$ (205,728)	$ (209,002)	$ (207,419)
Accounting Standards Update 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Reduction of accumulated deficit related to capitalization of incremental contract costs	692
Accounting Standards Update 2014-09 | ASC 606 adoption adjustments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit		$ (1,439)
ASC 606 Adoption Adjustments | Accounting Standards Update 2014-09 | ASC 606 adoption adjustments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accumulated deficit	$ 1,691