Most of the related party balances and transactions are with related companies and principal shareholders. Yehuda Zisapel is a principal shareholder of the Company. Zohar Zisapel is the Chairman of the Board of Directors and a principal shareholder of the Company. Yehuda and Zohar Zisapel are brothers who do not have a voting agreement between them. Jointly or severally, they are also founders, directors and principal shareholders of several other companies that are known as the RAD-BYNET group.

Members of the RAD-BYNET group provide the Company on an as-needed basis with information systems, marketing, and administrative services, the Company reimburses each company for its costs in providing these services. The aggregate amount of these expenses was approximately $ 1,699, $ 1,060 and $ 1,668 in 2014, 2015 and 2016, respectively.

The Company leases its offices in Israel from real estate holding companies controlled by Yehuda and Zohar Zisapel. The leases for the majority of this facility expire in December 2017, with an option to terminate early after three years.

Additionally, the Company leases the U.S. subsidiary's office space from a real estate holding company controlled by Yehuda and Zohar Zisapel. The lease for this facility was terminated in April 2015.

The aggregate amount of rent and maintenance expenses related to these properties was approximately $ 2,046 in 2014, $ 2,182 in 2015 and $ 1,963 in 2016.

The Company has an OEM arrangement with RADWIN, a member of RAD-BYNET group, according to which the Company purchases RADWIN products which are then resold to the Company’s customers. In addition, the Company purchases certain inventory components from other members of the RAD-BYNET group, which are integrated into its products. The aggregate purchase price of these components was approximately $ 4,149, $ 2,911 and $ 2,866 for the years ended December 31, 2014, 2015 and 2016, respectively.

The Company purchases certain property and equipment from members of the RAD-BYNET group, the aggregate purchase price of these assets was approximately $ 100, $ 51 and $ 1,019 for the years ended December 31, 2014, 2015 and 2016, respectively.

	Year ended December 31,
	2014		2015		2016

Cost of revenues	$	4,613	$	3,343	$	3,561

Research and development expenses	$	1,244	$	1,465	$	1,093

Selling and marketing expenses	$	914	$	737	$	733

General and administrative expenses	$	1,123	$	606	$	1,109

Purchase of property and equipment	$	100	$	51	$	1,019

	December 31,
	2015		2016

Trade payables, other accounts payable and accrued expenses	$	1,915	$	1,209