COMMITMENTS AND CONTINGENCIES Purchase Commitments  We enter into purchase commitments for products and services in the ordinary course of business. These purchases generally cover production requirements for 60 to 120 days as well as materials necessary to service customer units through the product lifecycle and for warranty commitments. As of March 31, 2019 , we had approximately $45.0 million in purchase commitments that are expected to be delivered within the next 12 months. Legal Proceedings  We are not involved in any legal proceedings, including routine litigation arising in the normal course of business, that we believe will have a material adverse effect on our business, financial condition or results of operations. U.S. Government Contracting Matter  We have sold our products and related services to the U.S. Government (the Government) under General Services Administration (GSA) Federal Supply Schedule contracts (the GSA Contracts) since 2002 and are currently selling our products and related services to the Government under two such GSA Contracts. Each GSA Contract is subject to extensive legal and regulatory requirements and includes, among other provisions, a price reduction clause (the Price Reduction Clause), which generally requires us to reduce the prices billed to the Government under the GSA Contracts to correspond to the lowest prices billed to certain benchmark customers. Late in the fourth quarter of 2018, during an internal review we preliminarily determined that certain of our pricing practices may have resulted in the Government being overcharged under the Price Reduction Clauses of the GSA Contracts (the GSA Matter). As a result, we have begun remediation efforts, including but not limited to, the identification of additional controls and procedures to ensure future compliance with the pricing and other requirements of the GSA Contracts. We have also retained outside legal counsel to assist with these efforts and to conduct a review of our pricing and other practices under the GSA Contracts (the Review). On February 14, 2019, we reported the GSA Matter to the GSA and its Office of Inspector General. Over the six-year period ended December 31, 2018, our sales to the Government under the GSA Contracts were approximately $53.5 million in the aggregate. As a result of the GSA Matter, for fourth quarter 2018, we reduced our total sales by a $4.8 million estimated cumulative sales adjustment, representative of the last six years of estimated overcharges to the Government under the GSA Contracts. In addition, for the fourth quarter of 2018, we recorded $0.5 million of imputed interest related to the estimated cumulative sales adjustment, which increased other expense and resulted in an estimated total liability of $5.3 million for the GSA Matter. For the three months ended March 31, 2019, we recorded $0.1 million of imputed interest related to the estimated cumulative sales adjustment for the six-year period ended December 31, 2018. Our estimated total liability for the GSA Matter is based on our preliminary review as of the date of this Quarterly Report on Form 10-Q and is subject to change based on the results of the Review being conducted by our outside legal counsel and discussions with the Government. While we have reported this matter to the GSA, the Government may conduct its own investigation or review (including an audit). We intend to cooperate fully with any Government inquiry. The Governments review of, or investigation into, this matter could result in civil and criminal penalties, administrative sanctions, and contract remedies being imposed on us, including but not limited to, termination of the GSA Contracts, repayments of amounts already received under the GSA Contracts, forfeiture of profits, damages, suspension of payments, fines, and suspension or debarment from doing business with the Government and possibly U.S. state and local governments. We may also be subject to litigation and recovery under the federal False Claims Act and possibly similar state laws, which could include claims for treble damages, penalties, fees and costs. As a result, we cannot reasonably predict the outcome of the Governments review of, or investigation into, this matter at this time or the resulting future financial impact on us. Any of these outcomes could have a material adverse effect on our reputation, our sales, results of operations, cash flows and financial condition, and the trading price of our common stock. In addition, we have incurred, and will continue to incur, legal and related costs in connection with the Review and the Governments response to this matter.