Commitments and Contingencies Leases As of March 31, 2020, the Company leases an office and laboratory space in Vista, California, under leases that expire in January 2026, with an option to extend a portion of the lease for an additional 5-year period. In addition, the Company also leases an additional office space in Vista, California, under a lease that expires in January 2026 with an option to extend the lease for an additional 5-year period. The Company's lease payments under each of these leases are subject to escalation clauses. For the three months ended March 31, 2020 and 2019, rent expense was $0.1 million. Acquisition-related liabilities In connection with the acquisition of the medical diagnostics division of Cypress Bioscience, Inc. in 2010, the Company was required to pay certain amounts in the event that certain revenue milestones were achieved and upon the first commercial sale of a product associated with this acquisition. The acquisition also included amounts that may be due under several licensing agreements. All milestone payments other than one have been paid as of December 31, 2017. The remaining milestone obligation is for an additional $2.0 million payment due to Prometheus Laboratories, Inc. (Prometheus) for which the fair value was determined to be zero at March 31, 2020 and December 31, 2019. In addition, the Company has ongoing royalty payment obligations on net sales of products which incorporate certain acquired technologies ranging from 2.5% to 7.5%. Future royalties payable under these arrangements are limited to the lesser of an aggregate of $4.2 million (including an upfront payment of $100,000) or the total royalties earned through January 1, 2024. Licensing Agreements The Company has licensed technology for use in its diagnostic tests. In addition to the milestone payments required by these agreements as described above, individual license agreements generally provide for ongoing royalty payments on net sales of products which incorporate licensed technology, as defined, ranging from 3.0% to 20.0%. Royalties are accrued when earned and recorded in costs of revenue in the accompanying condensed statement of operations. Supply Agreement In 2019, the Company entered into an amended supply agreement with one supplier for reagents which includes a minimum annual purchase commitment of $4.2 million for each of the three years covered by the original agreement, which terminates in 2021. Contingencies In the normal course of business, the Company enters into contracts and agreements that contain a variety of representations and warranties and provide for general indemnifications; including subpoenas and other civil investigative demands, from governmental agencies, Medicare or Medicaid payers and managed care organizations reviewing billing practices or requesting comment on allegations of billing irregularities that are brought to their attention through billing audits or third parties. The Company's exposure under these agreements is unknown because it involves claims that may be made against the Company in the future, but have not yet been made. The Company accrues a liability for such matters when it is probable that future expenditures will be made and such expenditures can be reasonably estimated. Litigation The Company is not a party to any litigation and does not have contingent reserves established for any litigation liabilities. From time to time, the Company may be subject to various legal proceedings that arise in the ordinary course of business activities.