Collaborative arrangements - Changes in Balances of Company's Receivables and Contract Liabilities (Detail) $ in Thousands	9 Months Ended
Sep. 30, 2018 USD ($)
Contract liabilities:
Deductions	$ (32,000)
Celgene Corporation [Member]
Receivables
Balance at beginning of period under Topic 606	4,635
Additions	1,641
Deductions	(6,276)
Contract liabilities:
Balance at beginning of period under Topic 606	76,812
Deductions	(31,981)
Balance at end of period under Topic 606	44,831
Celgene Corporation [Member] \| Accrued Expenses [Member]
Contract liabilities:
Additions	8,031
Deductions	(2,824)
Balance at end of period under Topic 606	$ 5,207

Additions to accounts receivable net current.

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Deduction to accounts receivable net current.

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Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Amount of increase (decrease) in obligation to transfer good or service to customer for which consideration from customer has been received or is due, from business combination.

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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.

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