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Collaboration Agreements - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Collaboration agreements |  |  |
Contract assets | $ 0 | $ 0 | $ 0
Contract liabilities |  |  |
Deferred revenue, balance at beginning of period | 3,987 | 4,815 |
Deferred revenue, additions | 0 | 0 |
Deferred revenue, deductions | 43 | 828 |
Deferred revenue, balance at end of period | 3,944 | 3,987 |
Revenue recognized in the period from: |  |  |
Amounts included in the contract liability at the beginning of the period | 43 | 828 |
Performance obligations satisfied in previous periods | $ 0 | $ 0 |

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- Definition Amount of decrease in obligation to transfer good or service to customer for which consideration has been received or is receivable. + References No definition available. + Details
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- Definition Amount of increase in obligation to transfer good or service to customer for which consideration has been received or is receivable. + References No definition available. + Details
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- Definition Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130549-203045 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=123360276&loc=SL49130531-203044 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=123360276&loc=SL49130533-203044 + Details
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- Definition Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130549-203045 + Details
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