Fair value of financial assets and liabilities - Financial Assets and Liabilities Measured at Fair Value (Details) - Recurring - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021
Assets
Cash equivalents	$ 45,132	$ 173,755
Assets	162,319	198,831
Short-term Investments
Assets
Investments	94,371	15,110
Long-term investments
Assets
Investments	22,816	9,966
Level 1
Assets
Cash equivalents	45,132	173,755
Assets	162,319	198,831
Level 1 \| Short-term Investments
Assets
Investments	94,371	15,110
Level 1 \| Long-term investments
Assets
Investments	$ 22,816	$ 9,966

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123874694&loc=d3e19207-110258

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Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
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