Commitments

Our future material contractual obligations include the following:



Obligation	Total		2018		2019		2020		2021		2022		Beyond
Operating leases (2)	$	2,494	$	670	$	674	$	395	$	117	$	120	$	518
Credit facility	48,750		5,000		5,000		38,750		—		—		—
Acquisition consideration	15,000		15,000		—		—		—		—		—
Purchase obligations (1)	61,307		61,307		—		—		—		—		—
Total obligations	$	127,551	$	81,977	$	5,674	$	39,145	$	117	$	120	$	518

(1) At December 31, 2017, the Company has purchase obligations in the amount of $61,307 which represent the contractual commitments under contract manufacturing and supply agreements with suppliers. The obligation under the supply agreement is primarily for finished product, inventory, and research and development.

(2) The Company leases its office and lab space under lease agreements that expire on June 30, 2020 and December 31, 2027. Rental expense was $664, $634, and $514, for the year ended December 31, 2017, 2016, and 2015, respectively. The remaining future lease payments under the operating lease are $2,494 as of December 31, 2017, payable monthly through June 30, 2020 and December 31, 2027.