10. COMMITMENTS AND CONTINGENCIES

The following is a summary of commitments as of June 30, 2018 (in thousands):

	Payments Due by Period
	Total		Less than 1 year		1-3 years		3-5 years		After 5 years
Total debt	$	404,272	$	115,262	$	1,446	$	287,564	$	—
Operating leases		21,887		6,858		9,471		4,605		953
Purchase obligations		66,850		66,229		603		18		—
Acquisition-related obligations		15,816		5,206		8,449		1,201		960
Defined benefit plan obligation		11,782		156		334		381		10,911

Total contractual obligations	$	520,607	$	193,711	$	20,303	$	293,769	$	12,824


Other Commercial Commitments—letters of credit	$	114,596	$	68,203	$	30,413	$	467	$	15,513

Operating Leases—We lease facilities and certain equipment under various operating lease agreements. Certain leases provide for periodic rent increases and may contain escalation clauses and renewal options. Rent expense totaled $9.0 million, $10.2 million and $9.4 million for fiscal years 2016, 2017 and 2018, respectively.

Contingent Acquisition Obligations—Under the terms and conditions of the purchase agreements associated with certain acquisitions, we may be obligated to make additional payments based on the achievement of certain sales or profitability milestones through the acquired operations. The maximum amount of such future payments under arrangements with contingent consideration caps is $29.9 million as of June 30, 2018. In addition, one of the purchase agreements we entered into requires royalty payments through 2022 based on the license of, or sales of products containing, the technology of CXR Limited, a company acquired in 2004.

For acquisitions that occurred through the end of fiscal year 2009, we account for such contingent payments as an addition to the purchase price of the acquired business. For acquisitions after fiscal 2009, pursuant to the adoption Financial Accounting Standard 141R, which was codified into ASC 805, the estimated fair value of these obligations is recorded as a liability at the time of the acquisition with subsequent revisions recorded in Selling, general and administrative expense in the consolidated financial statements. The estimated fair value measurements of contingent earn-out obligations are primarily based on unobservable inputs, which may include projected revenues, gross margins, operating income, estimated probability of achieving and the estimated probability of earn-out payments being made. These projections and probabilities are used to estimate future contingent earnout payments, which are discounted back to present value to compute the contingent earnout liability. The following table reconciles the contingent earnout liabilities, which are included in Other accrued expenses and current liabilities, and Other long-term liabilities in the accompanying consolidated balance sheets, from June 30, 2017 to June 30, 2018:

Beginning fair value, June 30, 2017	$	11,840
Additions		7,724
Remeasurement of fair value for contingent earn-out obligations		(1,540	)
Payments on contingent earn-out obligations		(2,311	)

Ending fair value, June 30, 2018	$	15,713

Advances from Customers—We receive advances from customers associated with certain contracts. These advances are paid in cash by customers, and we account for these as liabilities until our contractual obligations are complete.

Environmental Contingencies—We are subject to various environmental laws. Our practice is to conduct appropriate environmental investigations at our manufacturing facilities in North America, Asia-Pacific, and Europe, and, to the extent practicable, on all new properties in order to identify, as of the date of such investigation, potential areas of environmental concern related to past and present activities or from nearby operations. In certain cases, we have conducted further environmental assessments consisting of soil and groundwater testing and other investigations deemed appropriate by independent environmental consultants.

We continue to investigate contamination of the soil and groundwater beneath the Hawthorne, California facility that resulted from unspecified on- and off-site releases occurring prior to our occupancy. We believe the releases are of a historical nature and not uncommon to the region in general. We continue to take voluntary actions, in cooperation with the local governing agency, to fully investigate the site in order to develop appropriate remedial actions.

We have not accrued for loss contingencies relating to the Hawthorne facility or any other environmental matters because we believe that, although unfavorable outcomes may be possible, they are not considered by our management to be probable and reasonably estimable. If one or more of these environmental matters are resolved in a manner adverse to us, the impact on our business, financial condition, results of operations and cash flow could be material.

Indemnifications and Certain Employment-Related Contingencies—In the normal course of business, we have agreed to indemnify certain parties with respect to certain matters. We have agreed to hold certain parties harmless against losses arising from a breach of representations, warranties or covenants, or intellectual property infringement or other claims made by third parties. These agreements may limit the time within which an indemnification claim can be made and the amount of the claim. In addition, we have entered into indemnification agreements with our directors and certain of our officers. It is not possible to determine the maximum potential amount under these indemnification agreements due to the limited history of prior indemnification claims and the unique facts and circumstances involved in each particular agreement. We have not recorded any liability for costs related to contingent indemnification obligations as of June 30, 2018.

On December 31, 2017, we and Deepak Chopra, our Chief Executive Officer, entered into an amendment to Mr. Chopra's employment agreement that, among other things, provides for a $13.5 million bonus payment to Mr. Chopra on or within 45 days of January 1, 2024 contingent upon Mr. Chopra's continued employment with us through that date, subject to accelerated payout terms in the event of Mr. Chopra's death or disability after January 1, 2019. The bonus is recorded in the financial statements over the remaining term of the employment agreement.

Legal Proceedings—In December 2017, a short seller released a report regarding our compliance with the FCPA. Following that report, we and certain of our executive officers have been named as defendants in several lawsuits in the District Court that were filed in December 2017 and February 2018. Each of the complaints closely tracks the allegations set forth in the short-seller's report. All of the actions, which were consolidated by the District Court in March 2018 in an action captioned Arkansas Teacher Retirement System et al. v. OSI Systems, Inc. et al., No. 17-cv-08841, allege violations of Sections 10(b) and 20(a) of Exchange Act, relating to certain of our public statements and filings with the SEC, and seek damages and other relief based upon the allegations in the complaints. In April and May 2018, two shareholder derivative complaints were filed purportedly on behalf of the Company against the current members of our Board of Directors (as individual defendants), a former member of our Board of Directors, and our Chief Financial Officer. The first, captioned Riley v. Chopra et al., No. 18-cv-03371, was filed in the District Court, and the second, captioned Genesee County Employees' Retirement System v. Chopra, et al., No. BC705958, was filed in the Superior Court of the State of California, County of Los Angeles. The complaints allege, among other things, breach of fiduciary duties relating to the allegations contained in the above-mentioned short seller report. The complaints seek damages, restitution, injunctive relief, attorneys' and experts' fees, costs, expenses, and other unspecified relief. We believe that these actions are without merit and intend to defend them vigorously, and we expect to incur costs associated with defending against these actions. At this early stage of the litigations, the ultimate outcomes are uncertain and we cannot reasonably predict the timing or outcomes, or estimate the amount of loss, if any, or their effect, if any, on our financial statements.

Following the short-seller report, both the SEC and the DOJ commenced investigations into our compliance with the FCPA. The SEC has subpoenaed documents from the Company, and we are responding to that subpoena and providing the same documents to the DOJ. At this time, we are unable to predict what, if any, action may be taken by the DOJ or SEC as a result of these FCPA-related investigations, or any penalties or remedial measures these agencies may seek. Separately, the SEC and DOJ are also conducting an investigation of trading in our securities and have each subpoenaed information regarding trading by executives, directors, and employees, as well as our operations and disclosures in and around the time of certain trades. With respect to these trading-related matters, we have taken action with respect to a senior-level employee. At this time, we are unable to predict what, if any, action may be taken by the DOJ or SEC as a result of these trading-related investigations, or any penalties or remedial measures these agencies may seek. We place a high priority on compliance with our anti-corruption and securities trading policies and are cooperating with each of the government investigations.

Our acquired subsidiary, AS&E, was the subject of an investigation by the Office of the Inspector General of the U.S. General Services Administration ("GSA"). The investigation related to AS&E's discount practices and compliance with the pricing provisions of AS&E's GSA Schedule contract prior to the date of acquisition. This matter was resolved in May 2018 for $3 million. We had previously accrued $8 million for this matter. Upon resolution, $5 million was recorded as a reduction in fiscal 2018 in impairment, restructuring and other charges.

We are involved in various other claims and legal proceedings arising in the ordinary course of business. In our opinion after consultation with legal counsel, the ultimate disposition of such proceedings is not likely to have a material adverse effect on our business, financial condition, results of operations or cash flows. We have not accrued for loss contingencies relating to such matters because we believe that, although unfavorable outcomes in the proceedings may be possible, they are not considered by management to be probable and reasonably estimable. If one or more of these matters are resolved in a manner adverse to our company, the impact on our business, financial condition, results of operations and cash flows could be material.