Supplier and Customer Concentrations	12 Months Ended
Jun. 30, 2018
Supplier And Customer Concentrations
Supplier and Customer Concentrations	We utilize a number of glass compositions in manufacturing our molded glass aspheres and lens array products. These glasses or equivalents are available from a large number of suppliers, including CDGM Glass Company Ltd., Ohara Corporation, and Sumita Optical Glass, Inc. Base optical materials, used in certain of our specialty products, are manufactured and supplied by a number of optical and glass manufacturers. ISP utilizes major infrared material suppliers located around the globe for a broad spectrum of infrared crystal and glass. The Company believes that a satisfactory supply of such production materials will continue to be available, at reasonable prices or, in some cases, at increased prices, although there can be no assurance in this regard. In fiscal 2018, sales to three customers comprised an aggregate of approximately 28% of our annual revenue, and 28% of accounts receivable as of June 30, 2018. In fiscal 2017, sales to three customers comprised an aggregate of approximately 26% of our annual revenue, and 26% of accounts receivable as of June 30, 2017. The loss of any of these customers, or a significant reduction in sales to any such customer, would adversely affect our revenues. In fiscal 2018, 58% of our net revenue was derived from sales outside of the United States, with 84% of our foreign sales derived from customers in Europe and Asia. In fiscal 2017, 61% of our net revenue was derived from sales outside of the United States, with 88% of our foreign sales derived from customers in Europe and Asia.

Supplier and Customer Concentrations

12 Months Ended

Jun. 30, 2018

Supplier And Customer Concentrations

We utilize a number of glass compositions in manufacturing our molded glass aspheres and lens array products. These glasses or equivalents are available from a large number of suppliers, including CDGM Glass Company Ltd., Ohara Corporation, and Sumita Optical Glass, Inc. Base optical materials, used in certain of our specialty products, are manufactured and supplied by a number of optical and glass manufacturers. ISP utilizes major infrared material suppliers located around the globe for a broad spectrum of infrared crystal and glass. The Company believes that a satisfactory supply of such production materials will continue to be available, at reasonable prices or, in some cases, at increased prices, although there can be no assurance in this regard.

In fiscal 2018, sales to three customers comprised an aggregate of approximately 28% of our annual revenue, and 28% of accounts receivable as of June 30, 2018. In fiscal 2017, sales to three customers comprised an aggregate of approximately 26% of our annual revenue, and 26% of accounts receivable as of June 30, 2017. The loss of any of these customers, or a significant reduction in sales to any such customer, would adversely affect our revenues.

In fiscal 2018, 58% of our net revenue was derived from sales outside of the United States, with 84% of our foreign sales derived from customers in Europe and Asia. In fiscal 2017, 61% of our net revenue was derived from sales outside of the United States, with 88% of our foreign sales derived from customers in Europe and Asia.