Revenue (Tables)

9 Months Ended

Sep. 30, 2020

Revenue

Summary of revenue by type

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
(in thousands)	2019		2020		2019		2020
Product revenue, net	$	1,445	$	(47)	$	1,445	$	61
Collaboration revenues		5,051		616		6,051		768
Research premium		424		211		1,168		802
Government grants		—		511		484		936
Total	$	6,920	$	1,291	$	9,148	$	2,567

Summary of gross-to-net ("GTN") adjustments

	Three Months Ended		Nine Months Ended
(in thousands)	September 30, 2020		September 30, 2020
Product revenue, gross	$	8	$	406
GTN accruals
Chargebacks and cash discounts		—		13
Medicaid and Medicare rebates		1		47
Other returns, rebates, discounts and adjustments		2		94
Total GTN accruals		3		154
Product revenue		5		252
Adjustments to prior period accruals
Returns reserve (1)		(52)		(391)
GTN accrual adjustments		—		200
Product revenue, net	$	(47)	$	61