Commitments and Contingencies

Contractual Obligations

Leases

We lease office space under noncancelable operating leases with various expiration dates. Certain of the office space lease agreements contain rent holidays or rent escalation provisions. Rent holiday and rent escalation provisions are considered in determining the straight-line expense to be recorded over the lease term. The lease term begins on the date of initial possession of the leased property for purposes of recognizing lease expense on a straight-line basis over the term of the lease. For the years ended December 31, 2017, 2016, and 2015, rent expense was $12.3 million, $9.9 million, and $7.5 million, respectively. Deferred rent of $6.4 million and $6.5 million as of December 31, 2017 and 2016, respectively, is included in other liabilities.

We leased computer equipment from various parties under capital lease agreements that expired in March 2015.

As of December 31, 2017, the future minimum lease payments by year under noncancelable operating leases are as follows for the years ending December 31 (in thousands):



2018	$	14,934
2019	18,938
2020	16,675
2021	14,927
2022	13,005
Thereafter	40,055
Total minimum lease payments	$	118,534

Purchase obligations

As of December 31, 2017, our contractual purchase obligations, primarily related to hosting infrastructure providers, are as follows for the years ending December 31 (in thousands):



2018	38,559
2019	28,530
2020	29,270
Total purchase obligations	$	96,359

Letters of Credit

As of December 31, 2017 and 2016, we had a total of $2.0 million and $2.7 million, respectively in unsecured letters of credit outstanding primarily related to our leased office space in San Francisco. These letters of credit renew annually and mature at various dates through October 31, 2022.

Litigation and Loss Contingencies

We accrue estimates for resolution of legal and other contingencies when losses are probable and estimable. From time to time, we may become a party to litigation and subject to claims that arise in the ordinary course of business, including intellectual property claims, labor and employment claims, and threatened claims, breach of contract claims, tax, and other matters. We currently have no material pending litigation.

We are not currently aware of any litigation matters or loss contingencies that would be expected to have a material adverse effect on our business, consolidated balance sheets, results of operations, comprehensive loss, or cash flows.

Indemnifications

In the ordinary course of business, we enter into contractual arrangements under which we agree to provide indemnification of varying scope and terms to customers, business partners and other parties with respect to certain matters, including, but not limited to, losses arising out of the breach of such agreements, intellectual property infringement claims made by third parties, and other liabilities relating to or arising from our products, or our acts or omissions. In these circumstances, payment may be conditional on the other party making a claim pursuant to the procedures specified in the particular contract. Further, our obligations under these agreements may be limited in terms of time and/or amount, and in some instances, we may have recourse against third parties for certain payments. In addition, we have indemnification agreements with our directors and executive officers that require us, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The terms of such obligations may vary. To date, we have not incurred any material costs, and we have not accrued any liabilities in the accompanying consolidated financial statements, as a result of these obligations.

Certain of our product offerings include service-level agreements warranting defined levels of uptime reliability and performance and permitting those customers to receive credits for future services in the event that we fail to meet those levels. To date, we have not accrued for any significant liabilities in the accompanying consolidated financial statements as a result of these service-level agreements.