Supplier and Customer Concentrations	12 Months Ended
Jun. 30, 2019
Risks and Uncertainties [Abstract]
Supplier and Customer Concentrations	The Company utilizes a number of glass compositions in manufacturing its 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 the Company’s 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 2019, sales to three customers comprised an aggregate of approximately 32% of the Company’s annual revenue, and 40% of accounts receivable as of June 30, 2019, with one customer at 17% of sales, another customer at 8% of sales and the third customer at 7% of sales. In fiscal 2018, sales to three customers comprised an aggregate of approximately 28% of the Company’s annual revenue, and 28% of accounts receivable as of June 30, 2018, with one customer at 16% of sales, another customer at 7% of sales and the third customer at 5% of sales. The loss of any of these customers, or a significant reduction in sales to any such customer, would adversely affect the Company’s revenues. In fiscal 2019, 62% of the Company’s net revenue was derived from sales outside of the U.S., with 94% of foreign sales derived from customers in Europe and Asia. In fiscal 2018, 58% of the Company’s net revenue was derived from sales outside of the U.S., with 84% of foreign sales derived from customers in Europe and Asia.

Supplier and Customer Concentrations

12 Months Ended

Jun. 30, 2019

The Company utilizes a number of glass compositions in manufacturing its 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 the Company’s 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 2019, sales to three customers comprised an aggregate of approximately 32% of the Company’s annual revenue, and 40% of accounts receivable as of June 30, 2019, with one customer at 17% of sales, another customer at 8% of sales and the third customer at 7% of sales. In fiscal 2018, sales to three customers comprised an aggregate of approximately 28% of the Company’s annual revenue, and 28% of accounts receivable as of June 30, 2018, with one customer at 16% of sales, another customer at 7% of sales and the third customer at 5% of sales. The loss of any of these customers, or a significant reduction in sales to any such customer, would adversely affect the Company’s revenues.

In fiscal 2019, 62% of the Company’s net revenue was derived from sales outside of the U.S., with 94% of foreign sales derived from customers in Europe and Asia. In fiscal 2018, 58% of the Company’s net revenue was derived from sales outside of the U.S., with 84% of foreign sales derived from customers in Europe and Asia.