Long-term debt (Details)	12 Months Ended
Dec. 31, 2021
Long-term debt (Details) [Line Items]
Term loan agreement description	In 2013, the Company entered into a term loan agreement with a financial institution for $4.1 million with a maturity date of November 26, 2028 (the “Term Loan”).
Interest rate	1.80%
One-year savings account plus [Member]
Long-term debt (Details) [Line Items]
Interest rate	0.43%
Two-year savings account plus [Member]
Long-term debt (Details) [Line Items]
Interest rate	0.61%
Remaining-year savings account plus [Member]
Long-term debt (Details) [Line Items]
Interest rate	1.80%

The average effective interest rate during the reporting period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=124435984&loc=d3e28551-108399

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1F
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=123466505&loc=SL123495355-112611

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

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