Financial Instruments - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Financial Instruments [Abstract]
Change in exchange rate	10.00%
Carrying value of net asset	$ 45,944	$ 12,457	$ 2,817
Canadian prime rate	8.05%
Convertible notes, fixed interest rate	5.00%
Change in Canadian prime rate	1.00%
Loss due to one percentage change in Canadian prime rate	$ 425
Hypothetical decrease in fair value of investments	10.00%
Estimated decrease in fair values of investments upon hypothetical decrease of 10% in the prices	$ 50
Hypothetical increase in common stock	10.00%
Estimated increase in fair values of warrant liability upon hypothetical increase of 10% in the price of common stock	$ 5,800