Operating leases – We lease offices, manufacturing plants, equipment, vehicles and warehouses under operating lease agreements expiring through December 2028. Rental expense amounted to approximately $10.3 million, $10.4 million and $10.5 million for the years ended December 31, 2018, 2017 and 2016, respectively. We do not have purchase options related to the operating lease agreements. The table below sets forth the approximate amount for future minimum lease payments under non-cancelable operating leases at December 31, 2018:

2019	$	10,988
2020		10,141
2021		6,778
2022		5,650
2023		3,534
Thereafter		4,452
	$	41,543

The table below sets forth the approximate amount of future minimum lease payments due under the non-lease portion of our operating leases at December 31, 2018:

2019	$	2,555
2020		2,550
2021		1,860
2022		1,728
2023		1,426
Thereafter		2,946
	$	13,065

In addition, we have the following land right leases. None of the leases requires a rental payment.

Location	Term (years)	Expiration Date
Chengdu, China	50	2061
Shanghai, China	50	2056
Shandong, China	50	2058
Shanghai, China	50	2058
Yangzhou, China	50	2065

Purchase commitments – We have entered into non-cancelable purchase contracts for capital expenditures, primarily for manufacturing equipment, for approximately $9.2 million at December 31, 2018. In addition to these purchase commitments, we have equity investment obligations for our Chengdu facilities of $25 million for 2019 and 2020, and capital investment obligations of $30 million, $25 million and $16 million for 2019, 2020 and 2021, respectively. As of December 31, 2018, we also had a commitment to purchase approximately $117.8 million of wafers to be used in our manufacturing process. These wafer purchases will occur during 2019 and 2020.

Contingencies - From time to time, we are involved in various legal proceedings that arise in the normal course of business. While we intend to defend any lawsuit vigorously, we presently believe that the ultimate outcome of any current pending legal proceeding will not have any material adverse effect on our financial position, cash flows or operating results. However, litigation is subject to inherent uncertainties, and unfavorable rulings could occur. An unfavorable ruling could include monetary damages, which could impact on our business and operating results for the period in which the ruling occurs or future periods. Based on information available, we evaluate the likelihood of potential outcomes. We record the appropriate liability when the amount is deemed probable and reasonably estimable. In addition, we do not accrue for estimated legal fees and other directly related costs as they are expensed as incurred. The Company is not currently a party to any pending litigation that the Company considers material.