Long Term Debt - Hercules Loan Agreement - Additional Information (Detail) - USD ($)	1 Months Ended		3 Months Ended		9 Months Ended
	Jun. 30, 2019	Oct. 31, 2018	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Schedule Of Long Term Debt [Line Items]
Loss on extinguishment of debt			$ 0	$ (566,000)	$ (162,000)	$ (566,000)
Hercules Loan Agreement
Schedule Of Long Term Debt [Line Items]
Proceeds from lines of credit		$ 10,000,000.0
Amended and Restated Loan Agreement
Schedule Of Long Term Debt [Line Items]
Line of credit facility, maximum borrowing capacity							$ 35,000,000.0
Long-term line of credit			20,000,000.0		20,000,000.0		20,000,000.0
Line of credit facility, outstanding							10,000,000.0
Debt instrument variable percentage	8.75%
Interest rate increase percentage	4.00%
Amended and Restated Loan Agreement | Prime Rate
Schedule Of Long Term Debt [Line Items]
Debt instrument variable percentage	2.75%
Amended and Restated Loan Agreement | New Borrowings
Schedule Of Long Term Debt [Line Items]
Line of credit facility, current borrowing capacity							10,000,000.0
The Amended Loan Agreement
Schedule Of Long Term Debt [Line Items]
Line of credit facility, maximum borrowing capacity			50,000,000.0		$ 50,000,000.0
Debt instrument variable percentage					8.75%
Interest rate increase percentage					4.00%
Contingent additional term loan advances, tranche one			7,500,000		$ 7,500,000
Contingent additional term loan advances, tranche two			7,500,000		7,500,000
Contingent additional term loan advances, tranche three			10,000,000.0		10,000,000.0
Line of credit facility periodic payment					$ 800,000
Line of credit principal amount drawn percentage					4.00%
Threshold outstanding principal amount of advances			25,000,000.0		$ 25,000,000.0
Cash on hand requirement			$ 30,000,000.0		$ 30,000,000.0
Cash on hand requirement, multiplier			6		6
Cash on hand requirement, reduction level			$ 20,000,000.0		$ 20,000,000.0
Cash on hand requirement, multiplier, reduction level			3		3
Maximum rights to purchase equity securities			$ 3,000,000.0		$ 3,000,000.0
Rights to purchase equity securities, amount exercised					1,000,000.0
Loss on extinguishment of debt					162,000
Interest expense, debt			$ 700,000	$ 400,000	$ 2,000,000.0	$ 700,000
Effective interest rate of loan			10.70%		10.70%
Principal payments					$ 0
The Amended Loan Agreement | Interest Expense
Schedule Of Long Term Debt [Line Items]
Amortization of debt discount			$ 100,000
Accretion in period					$ 400,000
The Amended Loan Agreement | Prime Rate
Schedule Of Long Term Debt [Line Items]
Debt instrument variable percentage					3.75%
The Amended Loan Agreement | Maximum | Period One
Schedule Of Long Term Debt [Line Items]
Debt instrument prepayment premium, percentage			2.00%		2.00%
The Amended Loan Agreement | Maximum | Period Two
Schedule Of Long Term Debt [Line Items]
Debt instrument prepayment premium, percentage			1.00%		1.00%
The Amended Loan Agreement | Maximum | Period Three
Schedule Of Long Term Debt [Line Items]
Debt instrument prepayment premium, percentage			0.50%		0.50%
The Amended Loan Agreement | Term Loan
Schedule Of Long Term Debt [Line Items]
Line of credit facility, maximum borrowing capacity			$ 25,000,000.0		$ 25,000,000.0
Additional borrowing capacity							$ 5,000,000.0