Stockholders' Equity - Additional Information (Detail) - USD ($)	Jul. 30, 2019	Jul. 29, 2019	Jun. 04, 2018
Sales Agreement [Member] | Canaccord [Member] | Subsequent Event [Member]
Class Of Stock [Line Items]
Sale of common stock authorized, amount	$ 30,000,000
Percentage of agent service fee	3.00%
Purchase Agreement | Lincoln Park [Member] | Subsequent Event [Member]
Class Of Stock [Line Items]
Sale of common stock authorized, amount		$ 30,000,000
Effective period for sale of common stock		36 months
Maximum number of shares issue per business day		200,000
Maximum amount of shares to be issue per business day		$ 2,000,000
Public Offering [Member]
Class Of Stock [Line Items]
Number of shares sold			7,015,000
Sale price of stock (in dollars per share)			$ 7.50
Proceeds from issuance of common stock			$ 52,600,000
Proceeds from issuance of common stock after underwriters discount and expenses			$ 49,200,000