Summary of significant accounting policies - Narrative (Details) - USD ($)	12 Months Ended
	Nov. 30, 2020	Dec. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease liabilities	$ 93,006
Right-of-use asset	$ 476,000
Likelihood of tax benefit being realized upon settlement	50.00%
Cumulative Effect, Period of Adoption, Adjusted Balance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Lease liabilities		$ 786,000
Right-of-use asset		$ 786,000