Collaboration agreements - 2016 Takeda and XMT-1522 Agreements - Accounting Analysis (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Collaboration agreements
Deferred revenue recognized	$ 11	$ 40,592
Collaboration revenue	11	41,035
Accounts payable	4,603		$ 7,296
2016 Restated Tokeda Agreement and XMT-1522 Agreement
Collaboration agreements
Deferred revenue recognized		$ 39,965
Accounts payable	$ 2,335		$ 2,335

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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+ References

No definition available.

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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
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Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

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