Equity Financing - Additional Information (Detail)	1 Months Ended						3 Months Ended
	Jan. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Sep. 30, 2019 USD ($) $ / shares shares	Jun. 30, 2019 USD ($) $ / shares shares	Jun. 30, 2018 USD ($) $ / shares shares	Mar. 31, 2018 USD ($) $ / shares shares	Mar. 31, 2022 USD ($)	Mar. 31, 2021 USD ($)	Jan. 28, 2021
Class Of Warrant Or Right [Line Items]
Offering costs allocated to common stock warrant liability and expensed | $								$ 769,000
Registration statement expiration term							On May 11, 2018, the Company filed a shelf Registration Statement on Form S-3 with the SEC which was declared effective on June 8, 2018 (“Shelf Registration Statement”). This shelf registration process allows the Company to sell any combination of common stock, preferred stock, warrants and units consisting of such securities in one or more offerings from time to time having aggregate offering prices of up to $50 million. This registration statement may no longer be used after June 8, 2021, the three-year anniversary of its effective date.
Maximum [Member]
Class Of Warrant Or Right [Line Items]
Proceeds from issuance, aggregate offering prices | $							$ 50,000,000
March 2018 Purchase Agreement [Member]
Class Of Warrant Or Right [Line Items]
Shares of common stock issued						1,201,634
Warrant issued, shares of common stock called by warrant						1,282,832
Warrants issued, exercise price | $ / shares						$ 10.7258
December 2020 Purchase Agreement [Member]
Class Of Warrant Or Right [Line Items]
Shares of common stock issued		2,618,658
Proceeds from issuance of common stock and warrants gross | $		$ 8,000,000.0
Offering closing period		Dec. 22, 2020
December 2020 Purchase Agreement [Member] | Warrants [Member]
Class Of Warrant Or Right [Line Items]
Warrant issued, shares of common stock called by warrant		2,618,658
Warrants issued, exercise price | $ / shares		$ 3.00
Warrants expiration period		5 years 6 months
September 2019 Purchase Agreement [Member]
Class Of Warrant Or Right [Line Items]
Shares of common stock issued			1,318,828
Proceeds from issuance of common stock and warrants gross | $			$ 10,000,000.0
Offering closing period			Sep. 05, 2019
September 2019 Purchase Agreement [Member] | Warrants [Member]
Class Of Warrant Or Right [Line Items]
Warrant issued, shares of common stock called by warrant			659,414
Warrants issued, exercise price | $ / shares			$ 7.52
Warrants expiration period			5 years 6 months
June 2019 Purchase Agreement [Member]
Class Of Warrant Or Right [Line Items]
Shares of common stock issued				1,489,575
Proceeds from issuance of common stock and warrants gross | $				$ 7,500,000
Offering closing period				Jun. 14, 2019
June 2019 Purchase Agreement [Member] | Warrants [Member]
Class Of Warrant Or Right [Line Items]
Warrant issued, shares of common stock called by warrant				1,489,575
Warrants issued, exercise price | $ / shares				$ 5.00
Warrants expiration period				5 years 6 months
June 2018 Purchase Agreement [Member]
Class Of Warrant Or Right [Line Items]
Shares of common stock issued					1,392,345
Proceeds from issuance of common stock and warrants gross | $					$ 14,000,000.0
Offering closing period					Jun. 14, 2018
June 2018 Purchase Agreement [Member] | Warrants [Member]
Class Of Warrant Or Right [Line Items]
Warrant issued, shares of common stock called by warrant					1,392,345
Warrants issued, exercise price | $ / shares					$ 9.94
Warrants expiration period					5 years 6 months
June 2018 Placement Agent Warrants [Member] | June 2018 Purchase Agreement [Member] | Warrants [Member]
Class Of Warrant Or Right [Line Items]
Warrant issued, shares of common stock called by warrant					69,617
Warrants issued, exercise price | $ / shares					$ 12.568
Warrant, exercisable term					5 years
June 2019 Placement Agent Warrants [Member] | June 2019 Purchase Agreement [Member] | Warrants [Member]
Class Of Warrant Or Right [Line Items]
Warrant issued, shares of common stock called by warrant				74,479
Warrants issued, exercise price | $ / shares				$ 6.2938
Warrant, exercisable term				5 years
September 2019 Placement Agent Warrants [Member] | September 2019 Purchase Agreement [Member] | Warrants [Member]
Class Of Warrant Or Right [Line Items]
Warrant issued, shares of common stock called by warrant			65,942
Warrants issued, exercise price | $ / shares			$ 9.4781
Warrant, exercisable term			5 years
December 2020 Placement Agent Warrants [Member] | December 2020 Purchase Agreement [Member] | Warrants [Member]
Class Of Warrant Or Right [Line Items]
Warrant issued, shares of common stock called by warrant		130,933
Warrants issued, exercise price | $ / shares		$ 3.8188
Warrant, exercisable term		5 years
March 2018 Private Placement [Member] | March 2018 Purchase Agreement [Member]
Class Of Warrant Or Right [Line Items]
Shares of common stock issued						300,752
Warrant issued, shares of common stock called by warrant						300,752
Warrants issued, exercise price | $ / shares						$ 45.75
Proceeds from issuance of common stock and warrants gross | $						$ 10,000,000.0
Warrants expiration period						5 years
March 2018 Private Placement [Member] | March 2018 Placement Agent Warrants [Member] | March 2018 Purchase Agreement [Member]
Class Of Warrant Or Right [Line Items]
Warrant issued, shares of common stock called by warrant						15,038
Warrants issued, exercise price | $ / shares						$ 41.5625
Warrant, exercisable term						5 years
January 2021 Private Placement [Member] | January 2021 Purchase Agreement [Member]
Class Of Warrant Or Right [Line Items]
Shares of common stock issued	7,876,784
Warrant issued, shares of common stock called by warrant	3,938,392
Warrants issued, exercise price | $ / shares	$ 3.13
Proceeds from issuance of common stock and warrants gross | $	$ 25,100,000
Warrants expiration period	5 years 6 months
Remaining offering costs allocated to common stock and offset to additional paid in capital | $	$ 2,000,000.0
January 2021 Private Placement [Member] | January 2021 Purchase Agreement [Member] | Warrants [Member]
Class Of Warrant Or Right [Line Items]
Offering costs allocated to common stock warrant liability and expensed | $	$ 769,000
January 2021 Private Placement [Member] | January 2021 Purchase Agreement [Member] | Warrants [Member] | Expected Volatility [Member]
Class Of Warrant Or Right [Line Items]
Warrants and rights outstanding, measurement input									123.8
January 2021 Private Placement [Member] | January 2021 Purchase Agreement [Member] | Warrants [Member] | Stock Price [Member]
Class Of Warrant Or Right [Line Items]
Warrants and rights outstanding, measurement input									2.88
January 2021 Private Placement [Member] | January 2021 Purchase Agreement [Member] | Warrants [Member] | Risk-Free Interest Rate [Member]
Class Of Warrant Or Right [Line Items]
Warrants and rights outstanding, measurement input									0.5
January 2021 Private Placement [Member] | January 2021 Placement Agent Warrants [Member] | January 2021 Purchase Agreement [Member]
Class Of Warrant Or Right [Line Items]
Warrant issued, shares of common stock called by warrant	393,839
Warrants issued, exercise price | $ / shares	$ 3.99
Warrant, exercisable term	5 years 6 months
Issuance of placement agent warrants | $	$ 942,000
Offering costs | $	1,900,000
January 2021 Private Placement [Member] | January 2021 Placement Agent Warrants [Member] | January 2021 Purchase Agreement [Member] | Warrants [Member]
Class Of Warrant Or Right [Line Items]
Offering costs | $	$ 2,800,000