Summary of Assumptions to Estimate the Fair Value of Warrant Liability (Detail) - Fair Value, Inputs, Level 3 shares in Thousands	Sep. 30, 2019 shares
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Number of shares	5,841,250
Expected term	2 years 4 months 24 days
Expected volatility	0.7
Risk-free interest rate	0.016
Dividend yield	0

Period between issuance and expiration of outstanding warrant and right embodying unconditional obligation requiring redemption by transferring asset at specified or determinable date or upon event certain to occur, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)(2)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

Name:	us-gaap_WarrantsAndRightsOutstandingTerm
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant