Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Schedule of Future Minimum Lease Payments Under Non-Cancelable Operating Leases

As of December 31, 2017, future minimum lease payments under non-cancelable operating leases are as follows (in thousands):

	Operating
	Leases
2018	$	2,172
2019		2,297
2020		2,310
2021		1,720
2022		621
Thereafter		479
Total minimum lease payments	$	9,599

The Trustees of the University of Pennsylvania [Member]

Summary of Expenses Incurred by Company

Expenses incurred by the Company related to its license from Penn were as follows (in thousands):

	Years Ended December 31,
	2017		2016		2015
Sublicense fees	$	207	$	430	$	703
Royalties on sales of reagents		4		11		9
Maintenance of licensed patents		233		133		154
	$	444	$	574	$	866

GlaxoSmithKline LLC [Member]

Summary of Expenses Incurred by Company

Expenses incurred by the Company related to its license from GSK were as follows (in thousands):

	Years Ended December 31,
	2017		2016		2015
Sublicense fees	$	997	$	430	$	703
Royalties on sales of reagents		2		7		5
Milestone fees		500		—		—
Maintenance of licensed patents		509		597		573
	$	2,008	$	1,034	$	1,281