Warrants - Additional Information (Detail)	1 Months Ended		3 Months Ended		12 Months Ended
	Jul. 31, 2020 USD ($) $ / shares shares	May 31, 2020 USD ($) $ / shares shares	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) shares
Class Of Warrant Or Right [Line Items]
Investors exercised warrants and purchase shares of common stock | shares					(30,000)
Gross proceeds from warrants exercise | $					$ 22,000	$ 9,372,000
July 2020 Warrant Exercise Transaction [Member]
Class Of Warrant Or Right [Line Items]
Gain (loss) on extinguishment of warrant liability | $			$ 682,000
July 2020 Warrant Exercise Transaction [Member] | Warrants [Member]
Class Of Warrant Or Right [Line Items]
Warrants issued, exercise price | $ / shares	$ 3.85
Warrant issued, shares of common stock called by warrant | shares	641,416
Warrant, exercisable term	5 years 6 months
Value of warrants | $	$ 2,100
July 2020 Warrant Exercise Transaction [Member] | Warrants [Member] | Expected Volatility [Member]
Class Of Warrant Or Right [Line Items]
Warrants and rights outstanding, measurement input	1.26
July 2020 Warrant Exercise Transaction [Member] | Warrants [Member] | Stock Price [Member]
Class Of Warrant Or Right [Line Items]
Warrants and rights outstanding, measurement input	3.73
July 2020 Warrant Exercise Transaction [Member] | Warrants [Member] | Risk-Free Interest Rate [Member]
Class Of Warrant Or Right [Line Items]
Warrants and rights outstanding, measurement input	0.0035
May 2020 Warrant Exercise Transaction [Member]
Class Of Warrant Or Right [Line Items]
Gain (loss) on extinguishment of warrant liability | $				$ 47,000
May 2020 Warrant Exercise Transaction [Member] | Warrants [Member]
Class Of Warrant Or Right [Line Items]
Warrants issued, exercise price | $ / shares		$ 4.775
Warrant issued, shares of common stock called by warrant | shares		1,392,345
Warrant, exercisable term		5 years
Value of warrants | $		$ 4,400,000
May 2020 Warrant Exercise Transaction [Member] | Warrants [Member] | Expected Volatility [Member]
Class Of Warrant Or Right [Line Items]
Warrants and rights outstanding, measurement input		1.28
May 2020 Warrant Exercise Transaction [Member] | Warrants [Member] | Stock Price [Member]
Class Of Warrant Or Right [Line Items]
Warrants and rights outstanding, measurement input		3.81
May 2020 Warrant Exercise Transaction [Member] | Warrants [Member] | Risk-Free Interest Rate [Member]
Class Of Warrant Or Right [Line Items]
Warrants and rights outstanding, measurement input		0.0038
March 2018 Warrants [Member]
Class Of Warrant Or Right [Line Items]
Investors exercised warrants and purchase shares of common stock | shares						641,416
Warrants issued, exercise price | $ / shares					$ 10.73
March 2018 Warrants [Member] | July 2020 Warrant Exercise Transaction [Member] | Warrants [Member]
Class Of Warrant Or Right [Line Items]
Investors exercised warrants and purchase shares of common stock | shares	641,416
Warrants issued, exercise price | $ / shares	$ 3.975
Gross proceeds from warrants exercise | $	$ 2,600,000
June 2018 Warrants [Member]
Class Of Warrant Or Right [Line Items]
Investors exercised warrants and purchase shares of common stock | shares						1,392,345
Warrants issued, exercise price | $ / shares					$ 9.94
June 2018 Warrants [Member] | May 2020 Warrant Exercise Transaction [Member] | Warrants [Member]
Class Of Warrant Or Right [Line Items]
Investors exercised warrants and purchase shares of common stock | shares		1,392,345
Warrants issued, exercise price | $ / shares		$ 4.90
Gross proceeds from warrants exercise | $		$ 6,800,000
Placement Agent [Member] | July 2020 Warrant Exercise Transaction [Member] | Warrants [Member]
Class Of Warrant Or Right [Line Items]
Warrants issued, exercise price | $ / shares	$ 4.969
Warrant issued, shares of common stock called by warrant | shares	32,071
Warrant, exercisable term	5 years 6 months
Value of warrants | $	$ 101,000
Placement Agent [Member] | May 2020 Warrant Exercise Transaction [Member] | Warrants [Member]
Class Of Warrant Or Right [Line Items]
Warrants issued, exercise price | $ / shares		$ 6.125
Warrant issued, shares of common stock called by warrant | shares		69,617
Warrant, exercisable term		5 years
Value of warrants | $		$ 215,000