Collaborative arrangements - Changes in Balances of Company's Receivables and Contract Liabilities (Detail) - Bristol-Myers Squibb $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($)
Receivables
Balance at beginning of period	$ 400
Additions	12,000
Deductions	(6,800)
Balance at end of period	5,600
Contract liabilities:
Balance at beginning of period	18,265
Additions	200,000
Deductions	(191,442)
Balance at end of period	$ 26,823