6. Commitments and Contingencies

Lease and purchase obligations—The Company leases office and research facilities under operating leases for its U.S. headquarters and international locations that expire at various dates through March 2024. Under any lease agreement that contains escalating rent provisions, lease expense is recorded on a straight-line basis over the lease term. Rent expense for the three months ended September 30, 2018 and 2017 was $0.4 million and $0.3 million, respectively. Rent expense for the nine months ended September 30, 2018 and 2017 was $1.4 million and $0.8 million, respectively. In addition, the Company has purchase obligations which included agreements and issued purchase orders containing non-cancelable payment terms to purchase goods and services.

As of September 30, 2018, future minimum operating lease payments and purchase obligations are as follows (in thousands):

					Total
	Operating		Purchase		Lease and Purchase
	Leases		Obligations		Obligations
2018 (remaining)	$	138	$	8,533	$	8,671
2019		1,446		5,361		6,807
2020		1,496		3,981		5,477
2021		1,995		399		2,394
2022 and thereafter		4,251		—		4,251
Total	$	9,326	$	18,274	$	27,600

Litigation—The Company accrues for contingencies when it believes that a loss is probable and that it can reasonably estimate the amount of any such loss and the Company has made an assessment of the probability of incurring any such losses and whether or not those losses are estimable.

Although the Company is not currently subject to any litigation, and the Company is not aware of any litigation currently threatened against it, the Company may be subject to legal proceedings, claims and litigation, including intellectual property litigation, arising in the ordinary course of business. Such matters are subject to many uncertainties and outcomes and are not predictable with assurance. The Company accrues amounts that it believes are adequate to address any liabilities related to legal proceedings and other loss contingencies that it believes will result in a probable loss that is reasonably estimable.

To the extent there is a reasonable possibility that a loss exceeding amounts already recognized may be incurred and the amount of such additional loss would be material, the Company will either disclose the estimated additional loss or state that such an estimate cannot be made. The Company does not currently believe that it is reasonably possible that losses in connection with litigation arising in the ordinary course of business would be material.

Indemnification—Under the indemnification provisions of the Company’s standard sales-related contracts, the Company agrees to defend its customers against third-party claims asserting infringement of certain intellectual property rights, which may include patents, copyrights, trademarks, or trade secrets, and to pay judgments entered on such claims. Certain agreements include indemnification provisions that could potentially expose the Company to losses in excess of the amount received under the agreement. In addition, the Company indemnifies its directors and certain of its officers while they are serving in good faith in such capacities. To date, the Company has not incurred costs to defend lawsuits or settle claims related to these indemnification agreements. As of September 30, 2018 and December 31, 2017, no liability associated with such indemnifications had been recorded.