Recent Accounting Pronouncements - Additional Information (Details) - USD ($)	Nov. 01, 2019	Nov. 01, 2018	Apr. 30, 2020
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Operating lease liability	$ 10,300,000		$ 10,486,000
Operating lease ROU assets	10,100,000		$ 10,051,000
ASC 842 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Cumulative effect adjustment increase in Accumulated deficit	0
Operating lease liability	10,300,000
Operating lease ROU assets	$ 10,100,000
ASU 2014-09 [Member]
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Cumulative effect adjustment increase in Accumulated deficit		$ 6,700,000