Concentrations of Risks	6 Months Ended
Sep. 30, 2017
Risks and Uncertainties [Abstract]
Concentrations of Risks	Concentrations of Risks The Company sells to customers globally and, as the Company generally does not require collateral from its customers, on a monthly basis the Company evaluates customer account balances in order to assess the Company’s financial risks of collection. One customer, TTI, Inc., an electronics distributor, accounted for over 10% of the Company’s net sales in the quarters and six-month periods ended September 30, 2017 and 2016. There were no accounts receivable balances from any customer exceeding 10% of gross accounts receivable as of September 30, 2017 and March 31, 2017. Electronics distributors are an important channel in the electronics industry and accounted for 39% and 46% of the Company’s net sales in the six-month periods ended September 30, 2017 and 2016, respectively. As a result of the Company’s concentration of sales to electronics distributors, the Company may experience fluctuations in the Company’s operating results as electronics distributors experience fluctuations in end-market demand and/or adjust their inventory stocking levels. Legal Update In July 2013, TOKIN was named as one of eight defendants in two purported U.S. class action antitrust lawsuits (In Re: Lithium Ion Batteries Antitrust Litigation, 13-MD-02420-YGR, United States District Court, Northern District of California) (the “Battery Class Action Suits”) regarding the sale of lithium ion batteries brought on behalf of direct product purchasers and indirect product purchasers. On April 12, 2017, motions to approve class certification on behalf of the direct product purchasers and indirect product purchasers plaintiffs were denied by the Court; plaintiffs were given leave to amend. On August 17, 2017, TOKIN reached a preliminary settlement by which, in consideration of the release of TOKIN and its subsidiaries from claims asserted in the Battery Class Action Suits, TOKIN agreed to pay $4.95 million to the settlement class of direct product purchasers. The settlement is subject to execution of a definitive agreement and court approval. Pursuant to the terms of the preliminary settlement, the settlement amount is payable within 21 days after preliminary court approval. Beginning in March 2014, TOKIN and certain of its subsidiaries received inquiries, requests for information and other communications from government authorities in China, the United States, the European Commission, Japan, South Korea, Taiwan, Singapore and Brazil concerning alleged anti-competitive activities within the capacitor industry. On September 2, 2015, the United States Department of Justice announced a plea agreement with TOKIN in which TOKIN agreed to plead guilty to a one-count felony charge of unreasonable restraint of interstate and foreign trade and commerce in violation of Section 1 of the Sherman Act, and to pay a criminal fine of $13.8 million. The plea agreement was approved by the United States District Court, Northern District of California, on January 21, 2016. The fine is payable over five years in six installments of $2.3 million each, plus accrued interest. The first and second payments were made in February 2016 and January 2017, respectively, while the next payment is due in January 2018. On December 9, 2015, the Taiwan Fair Trade Commission (“TFTC”) publicly announced that TOKIN would be fined 1,218.2 million New Taiwan dollars (“NTD”) (approximately U.S. $40.2 million) for violations of the Taiwan Fair Trade Act. Subsequently, the TFTC has reduced the fine to NTD609.1 million (approximately U.S. $20.1 million). In February 2016, TOKIN commenced an administrative suit in Taiwan, challenging the validity of the amount of the fine. On March 29, 2016, the Japan Fair Trade Commission published an order by which TOKIN was fined ¥127.2 million (approximately U.S. $1.1 million) for violation of the Japanese Antimonopoly Act. Payment of the fine was made on October 31, 2016. On July 15, 2016, TOKIN entered into definitive settlement agreements in two antitrust suits filed with the United States District Court, Northern District of California as In re: Capacitors Antitrust Litigation, No. 3:14-cv-03264-JD (the “Capacitor Class Action Suits”). Pursuant to the terms of the settlement, in consideration of the release of TOKIN and its subsidiaries (including TOKIN America, Inc.) from claims asserted in the Capacitor Class Action Suits, TOKIN will pay an aggregate $37.3 million to a settlement class of direct purchasers of capacitors and a settlement class of indirect purchasers of capacitors. Each of the respective class payments is payable in five installments, two of which were paid on or before respective due dates of July 29, 2016 and 2017, the next two of which are due each year thereafter on the anniversary of the initial payment, and the final payment is due by December 31, 2019. On July 27, 2016, Brazil’s Administrative Council for Economic Defense approved a cease and desist agreement with TOKIN in which TOKIN made a financial contribution of Brazilian Real 0.6 million (approximately U.S. $0.2 million) to Brazil’s Fund for Defense of Diffuse Rights. The remaining governmental investigations are continuing at various stages. As of September 30, 2017, TOKIN’s accrual for antitrust and civil litigation claims totaled $81.6 million which is stated in the following line items, “Account payable” ($10.1 million), “Accrued expenses” ($35.4 million) and “Other non-current obligations” ($36.1 million) on the Condensed Consolidated Balance Sheets. This amount includes the best estimate of losses which may result from the ongoing antitrust investigations, civil litigation and claims. However, the actual outcomes could differ from what has been accrued. Additionally, under the terms of the TOKIN Purchase Agreement, TOKIN will be responsible for defending all suits, paying all expenses and satisfying all judgments to the extent arising out of or related the capacitor antitrust investigations and related litigation described above.

Concentrations of Risks

The Company sells to customers globally and, as the Company generally does not require collateral from its customers, on a monthly basis the Company evaluates customer account balances in order to assess the Company’s financial risks of collection. One customer, TTI, Inc., an electronics distributor, accounted for over 10% of the Company’s net sales in the quarters and six-month periods ended September 30, 2017 and 2016. There were no accounts receivable balances from any customer exceeding 10% of gross accounts receivable as of September 30, 2017 and March 31, 2017.

Electronics distributors are an important channel in the electronics industry and accounted for 39% and 46% of the Company’s net sales in the six-month periods ended September 30, 2017 and 2016, respectively. As a result of the Company’s concentration of sales to electronics distributors, the Company may experience fluctuations in the Company’s operating results as electronics distributors experience fluctuations in end-market demand and/or adjust their inventory stocking levels.

Legal Update

In July 2013, TOKIN was named as one of eight defendants in two purported U.S. class action antitrust lawsuits (In Re: Lithium Ion Batteries Antitrust Litigation, 13-MD-02420-YGR, United States District Court, Northern District of California) (the “Battery Class Action Suits”) regarding the sale of lithium ion batteries brought on behalf of direct product purchasers and indirect product purchasers. On April 12, 2017, motions to approve class certification on behalf of the direct product purchasers and indirect product purchasers plaintiffs were denied by the Court; plaintiffs were given leave to amend. On August 17, 2017, TOKIN reached a preliminary settlement by which, in consideration of the release of TOKIN and its subsidiaries from claims asserted in the Battery Class Action Suits, TOKIN agreed to pay $4.95 million to the settlement class of direct product purchasers. The settlement is subject to execution of a definitive agreement and court approval. Pursuant to the terms of the preliminary settlement, the settlement amount is payable within 21 days after preliminary court approval.

Beginning in March 2014, TOKIN and certain of its subsidiaries received inquiries, requests for information and other communications from government authorities in China, the United States, the European Commission, Japan, South Korea, Taiwan, Singapore and Brazil concerning alleged anti-competitive activities within the capacitor industry.

On September 2, 2015, the United States Department of Justice announced a plea agreement with TOKIN in which TOKIN agreed to plead guilty to a one-count felony charge of unreasonable restraint of interstate and foreign trade and commerce in violation of Section 1 of the Sherman Act, and to pay a criminal fine of $13.8 million. The plea agreement was approved by the United States District Court, Northern District of California, on January 21, 2016. The fine is payable over five years in six installments of $2.3 million each, plus accrued interest. The first and second payments were made in February 2016 and January 2017, respectively, while the next payment is due in January 2018.

On December 9, 2015, the Taiwan Fair Trade Commission (“TFTC”) publicly announced that TOKIN would be fined 1,218.2 million New Taiwan dollars (“NTD”) (approximately U.S. $40.2 million) for violations of the Taiwan Fair Trade Act. Subsequently, the TFTC has reduced the fine to NTD609.1 million (approximately U.S. $20.1 million). In February 2016, TOKIN commenced an administrative suit in Taiwan, challenging the validity of the amount of the fine.

On March 29, 2016, the Japan Fair Trade Commission published an order by which TOKIN was fined ¥127.2 million (approximately U.S. $1.1 million) for violation of the Japanese Antimonopoly Act. Payment of the fine was made on October 31, 2016.

On July 15, 2016, TOKIN entered into definitive settlement agreements in two antitrust suits filed with the United States District Court, Northern District of California as In re: Capacitors Antitrust Litigation, No. 3:14-cv-03264-JD (the “Capacitor Class Action Suits”). Pursuant to the terms of the settlement, in consideration of the release of TOKIN and its subsidiaries (including TOKIN America, Inc.) from claims asserted in the Capacitor Class Action Suits, TOKIN will pay an aggregate $37.3 million to a settlement class of direct purchasers of capacitors and a settlement class of indirect purchasers of capacitors. Each of the respective class payments is payable in five installments, two of which were paid on or before respective due dates of July 29, 2016 and 2017, the next two of which are due each year thereafter on the anniversary of the initial payment, and the final payment is due by December 31, 2019.

On July 27, 2016, Brazil’s Administrative Council for Economic Defense approved a cease and desist agreement with TOKIN in which TOKIN made a financial contribution of Brazilian Real 0.6 million (approximately U.S. $0.2 million) to Brazil’s Fund for Defense of Diffuse Rights.

The remaining governmental investigations are continuing at various stages. As of September 30, 2017, TOKIN’s accrual for antitrust and civil litigation claims totaled $81.6 million which is stated in the following line items, “Account payable” ($10.1 million), “Accrued expenses” ($35.4 million) and “Other non-current obligations” ($36.1 million) on the Condensed Consolidated Balance Sheets. This amount includes the best estimate of losses which may result from the ongoing antitrust investigations, civil litigation and claims. However, the actual outcomes could differ from what has been accrued. Additionally, under the terms of the TOKIN Purchase Agreement, TOKIN will be responsible for defending all suits, paying all expenses and satisfying all judgments to the extent arising out of or related the capacitor antitrust investigations and related litigation described above.