Commitments and Contingencies We lease our office and warehouse facilities under operating leases, which expire at various dates through 2021 . Our primary operating lease commitments at June 30, 2016 related to our headquarters in Santa Clara, California, our office in San Francisco, California, and our warehouse in Shepherdsville, Kentucky. We recognize rent expense on a straight-line basis over the lease period. Where leases contain escalation clauses, rent abatements, or concessions, such as rent holidays and landlord or tenant incentives or allowances, we apply them in the determination of straight-line rent expense over the lease term. As a result of our strategic partnership with Ingram and the exit of our Kentucky warehouse during 2015 , we have subleased substantially all of our warehouse in Kentucky and we expect this sublease agreement to generate $0.2 million of sublease income per month through the end of the lease term in November 2016. Rental expense, net of sublease income, was approximately $0.5 million and $0.9 million in the three and six months ended June 30, 2016 , respectively, and $0.5 million and $1.4 million in the three and six months ended June 30, 2015 , respectively. From time to time, third parties may assert patent infringement claims against us in the form of letters, litigation, or other forms of communication. In addition, we may from time to time be subject to other legal proceedings and claims in the ordinary course of business, including claims of alleged infringement of trademarks, copyrights, and other intellectual property rights; employment claims; and general contract or other claims. We may also, from time to time, be subject to various legal or government claims, disputes, or investigations. Such matters may include, but not be limited to, claims, disputes, or investigations related to warranty, refund, breach of contract, employment, intellectual property, government regulation, or compliance or other matters. In July 2010, the Kentucky Tax Authority issued a property