Stockholder's Equity - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended				6 Months Ended	9 Months Ended
	Jun. 24, 2019	Apr. 30, 2018	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Jun. 30, 2019	Sep. 30, 2019	Sep. 30, 2018
Offering expenses			$ 50
Number of common stock in warrant			40,834					40,834
Warrant granted			0					40,834
Additional paid in capital					$ 421			$ 400
Warrant exercised			0				59,707	59,707
Weighted average exercise price of exercised warrant							$ 3.01	$ 3.01
Warrant forfeited			0					4,474
Underwritten Public Offering [Member]
Net proceeds from common stock shares issued at public offering								$ 32,169	$ 53,573
Underwritten Public Offering [Member] | Common stock [Member]
Common stock, shares issued	3,833,334	5,899,500		3,833,334		5,899,500
Common stock public offering price	$ 9.00	$ 9.75
Net proceeds from common stock shares issued at public offering	$ 32,200	$ 53,600
Underwriting discounts and commissions	2,100
Offering expenses	$ 200