Related-Party Transactions	12 Months Ended
Dec. 31, 2017
Related Party Transactions [Abstract]
Related-Party Transactions	RELATED-PARTY TRANSACTIONS The CEO leases the annual right to use 25% of the Company's aircraft under a October 2014 lease, which was superseded by a new lease signed in July 2017 in connection with the purchase of a different aircraft. The new lease expires July 2022. The annual lease rate under the 2017 lease was $924 and future rent payments are adjusted annually. The annual lease rate under the 2014 lease was $651. The CEO paid the Company $753 in 2017 and $651 in both 2016 and 2015 under the aircraft leases. In addition, the CEO directly pays an unrelated flight management firm for the operating costs of his private use including pilot fees, fuel and other costs. In 2017, 2016 and 2015, the Company purchased various equipment, parts and services from a company for which one of the Company's independent directors is an executive officer. The payments made for such equipment, parts and services for 2017, 2016 and 2015, totaled $2,296, $5,392 and $683, respectively. There were no amounts due to this company at December 31, 2017 or at December 31, 2016. In 2017, the Company sold products of $503 to the same company. No sales were made in either 2016 or 2015. In 2016, the Company purchased an office building located in Marlborough, Massachusetts from a subsidiary of IP Fibre Devices (UK) Ltd. ("IPFD") for $23,750. The purchase price was based on the fair market value of the building determined using an independent appraisal. The appraisal was commissioned by the Nominating and Corporate Governance Committee of the Board of Directors. The Company's Chief Executive Officer ("CEO") is the managing director of IPFD. The CEO and certain founding members of the Company, which include the Senior Vice President, Chief Technology Officer and the Senior Vice President, Chief Operating Officer and Managing Director of IPG Laser GmbH, own shares in IPFD which is a stockholder of the Company. The Company leased space in the building prior to purchasing it and reimbursed the landlord for its portion of certain operational costs. The Company paid IPFD $443 and $531 for 2016 and 2015, respectively, under the office lease. In 2015, the Company sold products and services of $497 to OAO "RCE" Laser Processing Center ("Laser Center"), an application development and parts processing company. There were no transactions in 2017 or 2016. The Company's CEO owns approximately 39% of Laser Center, which he acquired from an unrelated third party in 2014. In 2016, the Company sold products of $146 to a separate company with whom another of the Company's independent directors was affiliated. No sales were made in either 2017 or 2015.

RELATED-PARTY TRANSACTIONS

The CEO leases the annual right to use 25% of the Company's aircraft under a October 2014 lease, which was superseded by a new lease signed in July 2017 in connection with the purchase of a different aircraft. The new lease expires July 2022. The annual lease rate under the 2017 lease was $924 and future rent payments are adjusted annually. The annual lease rate under the 2014 lease was $651. The CEO paid the Company $753 in 2017 and $651 in both 2016 and 2015 under the aircraft leases. In addition, the CEO directly pays an unrelated flight management firm for the operating costs of his private use including pilot fees, fuel and other costs.

In 2017, 2016 and 2015, the Company purchased various equipment, parts and services from a company for which one of the Company's independent directors is an executive officer. The payments made for such equipment, parts and services for 2017, 2016 and 2015, totaled $2,296, $5,392 and $683, respectively. There were no amounts due to this company at December 31, 2017 or at December 31, 2016. In 2017, the Company sold products of $503 to the same company. No sales were made in either 2016 or 2015.

In 2016, the Company purchased an office building located in Marlborough, Massachusetts from a subsidiary of IP Fibre Devices (UK) Ltd. ("IPFD") for $23,750. The purchase price was based on the fair market value of the building determined using an independent appraisal. The appraisal was commissioned by the Nominating and Corporate Governance Committee of the Board of Directors. The Company's Chief Executive Officer ("CEO") is the managing director of IPFD. The CEO and certain founding members of the Company, which include the Senior Vice President, Chief Technology Officer and the Senior Vice President, Chief Operating Officer and Managing Director of IPG Laser GmbH, own shares in IPFD which is a stockholder of the Company. The Company leased space in the building prior to purchasing it and reimbursed the landlord for its portion of certain operational costs. The Company paid IPFD $443 and $531 for 2016 and 2015, respectively, under the office lease.

In 2015, the Company sold products and services of $497 to OAO "RCE" Laser Processing Center ("Laser Center"), an application development and parts processing company. There were no transactions in 2017 or 2016. The Company's CEO owns approximately 39% of Laser Center, which he acquired from an unrelated third party in 2014.

In 2016, the Company sold products of $146 to a separate company with whom another of the Company's independent directors was affiliated. No sales were made in either 2017 or 2015.