Commitments and Contingencies

Operating Leases

The Company is obligated to make future minimum payments under three operating leases for 107,901 square feet of space used for general office, laboratory, manufacturing, operations, and research and development purposes primarily in Seattle, Washington. The leases expire beginning in 2019 to 2026 and include options to renew at the then current fair market rental for each of the facilities. The lease agreements contain rent abatement periods, scheduled rent increases and provide for tenant improvement allowances. Accordingly, the Company has recorded a deferred rent liability of $8.2 million and $8.7 million as of December 31, 2018 and 2017, respectively. This deferred rent liability is amortized over the term of the related lease.

Rent expense totaled approximately $4.9 million, $4.8 million, and $3.8 million for the years ended December 31, 2018, 2017, and 2016, respectively.

Future minimum lease payments under noncancelable operating leases as of December 31, 2018 were as follows (in thousands):



2019	$	5,526
2020	5,560
2021	5,593
2022	5,708
2023	5,869
Thereafter	13,458
	$	41,714

Purchase Commitments

The Company has non-cancellable purchase obligations totaling $17.7 million at December 31, 2018 related to binding commitments to purchase inventory and other research and development items.

Contingencies

From time to time, the Company may become involved in litigation relating to claims arising from the ordinary course of business. Additionally, the Company operates in various states and local jurisdictions for which sales, occupation, or franchise taxes may be payable to certain taxing authorities. Management believes that there are no claims or actions pending against the Company currently, the ultimate disposition of which would have a material adverse effect on the Company’s consolidated results of operation, financial condition or cash flows.