Warrants to Purchase Convertible Preferred Stock - Additional Information (Detail) - shares	Sep. 30, 2019	Jul. 31, 2018
Common Stock [Member]
Class of Warrant or Right Line Items
Number of preferred shares issuable under warrant	95,930	34,062
Series B Preferred Stock [Member]
Class of Warrant or Right Line Items
Number of preferred shares issuable under warrant	375,000

Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(i)(2))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

Name:	us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant