Leases - Narrative (Details) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Oct. 01, 2019	Sep. 30, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating leases right-of-use assets	$ 22,816		$ 17,398
Operating lease liabilities - current	1,311		3,645
Operating lease liabilities - long-term	22,128		14,372
Accumulated deficit	35,929		39,557	$ 39,555
Gain recognized on lease modification	121	$ 0
Operating lease liability	23,439
Increase to right-of-use assets	24,600
Increase to lease liabilities	$ 25,300
Facilities and Equipment | Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Remaining lease term	1 month 6 days
Facilities and Equipment | Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Remaining lease term	11 years
Lease Modification
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating leases right-of-use assets	$ 7,300
Gain recognized on lease modification	100
Operating lease liability	$ 7,200
ASC 842 Adjustments
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating leases right-of-use assets			17,398
Operating lease liabilities - current			3,645
Operating lease liabilities - long-term			14,372
Accumulated deficit			2
Operating lease liability			$ 18,000