Borrowings - Additional Information (Detail)			1 Months Ended						12 Months Ended
	May 13, 2021 USD ($) Tranche $ / shares shares	Mar. 07, 2019 USD ($) d $ / shares	Jun. 30, 2021 USD ($)	Jan. 31, 2021 USD ($) shares	Dec. 31, 2020 USD ($) $ / shares shares	Jun. 30, 2020 USD ($) shares	Apr. 09, 2020 USD ($)	Apr. 30, 2019 USD ($) shares	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Jul. 17, 2020 shares	Jul. 16, 2020 shares
Debt Instrument [Line Items]
Face amount	$ 20,000,000.0						$ 10,000,000.0		$ 31,185,000
Common stock, par value (in dollars per share) | $ / shares					$ 0.001				$ 0.001	$ 0.001
Vested Loan Agreement warrants	500,000								$ 766,000
Fair value of initial warrant liabilities recorded as deferred asset and reclassified to debt discount	$ 700,000
Debt instrument, description									Upon the funding of the $10.0 million for the second tranche in June 2021, the associated warrant liability of $0.3 million was reclassed to additional paid in capital at settlement and 56,803 shares of common stock were issued.
Reclass of warrant liability to additional paid in capital			$ 300,000						$ 298,000	$ 0
Common stock, shares issued (in shares) | shares					19,663,698				28,705,334	19,663,698	10,508,302	105,083,291
Date of issuance and sale of notes							Apr. 09, 2020
Proceeds from debt, net of issuance costs							$ 9,500,000
Payment of debt issuance costs							$ 500,000		$ 0	$ 494,000
Purchase price as percentage of principal amount							100.00%
Conversion of convertible note, amount				$ 6,000,000.0	$ 2,000,000.0	$ 2,000,000.0				4,000,000.0
Conversion of convertible note exchanged for shares | shares				959,080	322,348	316,461
Loss on debt extinguishment				$ 2,700,000	$ 1,000,000.0	$ 800,000			$ (2,725,000)	(1,766,000)
Interest rate							6.00%
Payment terms									The April 2020 Notes incurred interest at a rate of 6.0% per annum, payable semiannually in arrears on April 15 and October 15 of each year, beginning October 15, 2020.
Amortization of debt issuance costs and discount									$ 1,303,000	1,201,000
Fair value of convertible debt and derivative liability					7,400,000					7,400,000
Loss on extinguishment of debt				$ (2,700,000)	(1,000,000.0)	$ (800,000)			2,725,000	1,766,000
Net carrying amount of convertible debt and derivative liability					16,516,000				11,607,000	16,516,000
Deferred offering costs					187,000				150,000	187,000
2024									20,737,000
Other Liabilities
Debt Instrument [Line Items]
Deferred offering costs									$ 3,300,000
Interest rate, deferred fees									12.75%
Percentage of repayment of deferred fee, 2023									15.00%
Percentage of repayment of deferred fee, 2024									50.00%
Percentage of repayment of deferred fee, 2025									35.00%
2022									$ 500,000
2023									1,600,000
2024									1,200,000
Success premium									0
Silicon Valley Bank
Debt Instrument [Line Items]
Minimum outstanding term loan principal percentage for financial covenant waived	50.00%
Debt discount	$ 1,200,000
Loan and Security Agreement
Debt Instrument [Line Items]
Fair value of loan payable									$ 29,200,000
Loan and Security Agreement | Level 3 Inputs | Secured Spread
Debt Instrument [Line Items]
Debt instrument, measurement input									9.30
Loan and Security Agreement | Level 3 Inputs | Risk Free Rate
Debt Instrument [Line Items]
Debt instrument, measurement input									1.00
Loan and Security Agreement | Level 3 Inputs | Secured Yield
Debt Instrument [Line Items]
Debt instrument, measurement input									10.30
Loan and Security Agreement | Hercules Capital Inc. and Silicon Valley Bank
Debt Instrument [Line Items]
Common stock, par value (in dollars per share) | $ / shares	$ 0.001
Multiplier value by aggregate amount of the term loan advances divided by exercise price of warrants to calculate number of shares for purchase	0.04
Number of warrants issued to purchase common stock (in shares) | shares	113,607
Common stock, shares issued (in shares) | shares	56,803
Term Loan | Loan and Security Agreement
Debt Instrument [Line Items]
Notes maturity date	Mar. 03, 2025
Basis spread on variable rate (as a percent)	9.05%
Debt instrument maturity date subject to occurrence of certain conditions	May 01, 2025
Term Loan | Loan and Security Agreement | Prime Rate
Debt Instrument [Line Items]
Basis spread on variable rate (as a percent)	5.80%
Term Loan | Loan and Security Agreement | Hercules Capital Inc. and Silicon Valley Bank
Debt Instrument [Line Items]
Face amount	$ 60,000,000.0
Number of available tranches | Tranche	4
Initial Tranche of Term Loan | Loan and Security Agreement
Debt Instrument [Line Items]
Additional borrowing amount available	$ 20,000,000.0
Second Tranche of Term Loan | Loan and Security Agreement
Debt Instrument [Line Items]
Additional borrowing amount available	10,000,000.0
Third Tranche of Term Loan | Loan and Security Agreement
Debt Instrument [Line Items]
Additional borrowing amount available	5,000,000.0
Fourth Tranche of Term Loan | Loan and Security Agreement
Debt Instrument [Line Items]
Additional borrowing amount available	25,000,000.0
Increment debt amount	$ 5,000,000.0
April 2020 Note Purchase Agreement
Debt Instrument [Line Items]
Senior convertible notes					1,200,000					1,200,000
Unamortized debt issuance cost					100,000					100,000
Bifurcated embedded conversion option derivative liability					3,300,000					3,300,000
Derivative, fair value					8,100,000					8,100,000
Debt issuance costs					400,000					400,000
Gain (loss) on fair value adjustment of derivative liability										1,700,000
Amortization of debt issuance costs and discount										200,000
Senior Convertible Note Purchase Agreement
Debt Instrument [Line Items]
Face amount		$ 16,000,000.0
Notes maturity date		Mar. 15, 2025
Date of issuance and sale of notes		Mar. 07, 2019
Proceeds from debt, net of issuance costs		$ 14,700,000
Payment of debt issuance costs		$ 1,300,000
Purchase price as percentage of principal amount		100.00%
Conversion of convertible note, amount								$ 2,000,000.0
Conversion of convertible note exchanged for shares | shares								162,600
Loss on debt extinguishment								$ (200,000)
Interest rate		6.00%
Payment terms									The March 2019 Notes bear interest at a rate of 6.0% per annum payable semiannually in arrears on March 15 and September 15 of each year, beginning September 15, 2019. The March 2019 Notes will mature on March 15, 2025, unless earlier converted, redeemed or repurchased.
Senior convertible notes					9,400,000				$ 10,200,000	9,400,000
Unamortized debt issuance cost					400,000				300,000	400,000
Bifurcated embedded conversion option derivative liability					6,000,000.0				1,400,000	6,000,000.0
Derivative, fair value									7,000,000.0
Debt issuance costs									600,000
Gain (loss) on fair value adjustment of derivative liability									1,300,000	500,000
Amortization of debt issuance costs and discount									900,000	1,000,000.0
Fair value of convertible debt and derivative liability					$ 12,900,000				$ 12,300,000	$ 12,900,000
Loss on extinguishment of debt								200,000
Net carrying amount of convertible debt and derivative liability								2,800,000
Fair value of the consideration issued								$ 3,000,000.0
Notes maturity description									The March 2019 Notes will mature on March 15, 2025, unless earlier converted, redeemed or repurchased
Conversion terms									holder of the March 2019 Notes may convert their March 2019 Notes at their option at any time prior to the close of business on the business day immediately preceding March 15, 2025 into shares of the Company’s common stock.
Conversion rate, number of shares to be issued per $1000 of principal (in shares)		73.9096
Principal amount of notes used as the denominator for conversion into notes		$ 1,000
Initial conversion price of notes | $ / shares		$ 13.53
Conversion rate, number of shares to be issued per $1000 of principal (in shares) after adjustment to certain events		81
Principal amount of notes used as the denominator for conversion into notes after adjustment of certain events		$ 1,000
Convertible notes, redemption start date		Mar. 15, 2022
Convertible notes, threshold percentage of stock price trigger		130.00%
Convertible notes, threshold trading days | d		20
Convertible notes, threshold consecutive trading days | d		30
Redemption price as percentage of the principal amount		100.00%
Redemption price as percentage of the principal amount subject to certain exceptions		100.00%