Warrants - Schedule Of Fair Value Of Warrant Liability (Detail)	Sep. 30, 2020 USD ($) shares	Sep. 30, 2020 $ / shares	Dec. 31, 2019 USD ($)
Class of Warrant or Right [Line Items]
Warrants Outstanding | shares	2,485,794
Warrant Liability | $	$ 18,513,000		$ 15,879,843
Bridge Financing Warrants [member]
Class of Warrant or Right [Line Items]
Strike Price | $ / shares		$ 22.90
Warrants Outstanding | shares	218,964
Warrant Liability | $	$ 1,065,000		1,385,400
Private Placement Financing Warrants [member]
Class of Warrant or Right [Line Items]
Strike Price | $ / shares		19.39
Warrants Outstanding | shares	1,822,771
Warrant Liability | $	$ 13,457,000		12,189,169
Modification Warrants [member]
Class of Warrant or Right [Line Items]
Strike Price | $ / shares		12.04
Warrants Outstanding | shares	360,256
Warrant Liability | $	$ 3,251,500		$ 2,305,274
Additional Modification Warrants [member]
Class of Warrant or Right [Line Items]
Strike Price | $ / shares		$ 14.03
Warrants Outstanding | shares	83,803
Warrant Liability | $	$ 739,500