Letter of credit	3 Months Ended
Mar. 31, 2021
Debt Disclosure [Abstract]
Letter of credit	12. Letter of credit On April 19, 2018, the Corporation entered into a secured letter of credit agreement ("the Letter") for up to an aggregate amount of $2.5 million with a commercial lender that renews on an annual basis. The Letter bears an interest rate of 0.75%. There was an unused balance of $2.5 million at both March 31, 2021 and December 31, 2020.

The entire disclosure for short-term debt.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-URI http://asc.fasb.org/topic&trid=2208564

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