Contractual interest rate for funds borrowed, under the debt agreement.

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Long Term Debt - FFG Loan Agreement - Additional Information (Detail) - USD ($) $ in Thousands		1 Months Ended	3 Months Ended		9 Months Ended
	Mar. 08, 2019	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Apr. 30, 2019
Schedule Of Long Term Debt [Line Items]
Percentage of minimum cash balance							70.00%
Loss on extinguishment of debt			$ 566	$ 0	$ 566	$ 0
FFG Loan Agreement
Schedule Of Long Term Debt [Line Items]
Number of years accelerated payment	3 years
Number of years, payment term	5 years
Repayment of outstanding loan principal	$ 2,900	$ 566
Loss on extinguishment of debt		$ 566
FFG Loan Agreement \| Minimum
Schedule Of Long Term Debt [Line Items]
Debt instrument, interest rate		0.75%	0.75%		0.75%
FFG Loan Agreement \| Maximum
Schedule Of Long Term Debt [Line Items]
Debt instrument, interest rate		2.00%	2.00%		2.00%