v3.21.1

Summary of significant accounting policies - Marketable securities (Details) - USD ($) $ in Thousands | Mar. 31, 2021 | Dec. 31, 2020
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Summary of significant accounting policies |  |
Short-term marketable securities | $ 0 | $ 4,565
Unrealized gain, net of tax in accumulated other comprehensive loss |  | 1
Income tax effect related to unrealized gains in accumulated other comprehensive loss |  | $ 0

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- Definition Amount, after tax, of accumulated unrealized gain (loss) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=121641772&loc=d3e681-108580 + Details
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