Legal Proceedings	9 Months Ended
Sep. 30, 2015
Commitments and Contingencies Disclosure [Abstract]
Legal Proceedings	Legal Proceedings Although the Company expects to incur significant legal fees in connection with the below legal proceedings, the Company is unable to estimate the amount of such legal fees and therefore, such fees will be expensed in the period the legal services are performed. FCPA Matter As a result of being publicly traded in the U.S., the Company is subject to the U.S. Foreign Corrupt Practices Act (“FCPA”), which prohibits companies from making improper payments to foreign officials for the purpose of obtaining or retaining business. Beginning in 2009, the Company conducted an internal review into payments made to its former independent sales agent in China with respect to sales of its high-voltage capacitor products produced by its Swiss subsidiary. In January 2011, the Company reached settlements with the SEC and the U.S. Department of Justice (“DOJ”) with respect to charges asserted by the SEC and DOJ relating to the anti-bribery, books and records, internal controls, and disclosure provisions of the FCPA and other securities laws violations. The Company paid the monetary penalties under these settlements in installments such that all monetary penalties were paid in full by January 2013. With respect to the DOJ charges, a judgment of dismissal was issued in the U.S. District Court for the Southern District of California on March 28, 2014. On October 15, 2013, the Company received an informal notice from the DOJ that an indictment against the former Senior Vice President and General Manager of its Swiss subsidiary had been filed in the United States District Court for the Southern District of California. The indictment is against the individual, a former officer, and not against the Company and the Company does not foresee that further penalties or fines could be assessed against it as a corporate entity for this matter. However, the Company may be required throughout the term of the action to advance the legal fees and costs incurred by the individual defendant and to incur other financial obligations. While the Company maintains directors’ and officers’ insurance policies which are intended to cover legal expenses related to its indemnification obligations in situations such as these, the Company cannot determine if and to what extent the insurance policy will cover the legal fees for this matter. Accordingly, the legal fees that may be incurred by the Company in defending this former officer could have a material impact on its financial condition and results of operation. Swiss Bribery Matter In August 2013, the Company's Swiss subsidiary was served with a search warrant from the Swiss federal prosecutor’s office. At the end of the search, the Swiss federal prosecutor presented the Company with a listing of the materials gathered by the representatives and then removed the materials from its premises for keeping at the prosecutor’s office. Based upon the Company’s exposure to the case, the Company believes this action to be related to the same or similar facts and circumstances as the FCPA action previously settled with the SEC and the DOJ. During initial discussions, the Swiss prosecutor has acknowledged both the existence of the Company's DPA with the DOJ and its cooperation efforts thereunder, both of which should have a positive impact on discussions going forward. Additionally, other than the activities previously reviewed in conjunction with the SEC and DOJ matters under the FCPA, the Company has no reason to believe that additional facts or circumstances are under review by the Swiss authorities. In late March 2015, the Company was informed that the Swiss prosecutor intended to inform the parties in April 2015 as to whether the prosecutor’s office will bring charges or abandon the proceedings. However, to date, the Swiss prosecutor has not issued its formal decision. At this stage in the investigation, the Company is currently unable to determine the extent to which it will be subject to fines in accordance with Swiss bribery laws and what additional expenses will be incurred in order to defend this matter. As such, the Company cannot determine whether there is a reasonable possibility that a loss will be incurred nor can it estimate the range of any such potential loss. Accordingly, the Company has not accrued an amount for any potential loss associated with this action, but an adverse result could have a material adverse impact on its financial condition and results of operation. Government Investigations In early 2013, the Company voluntarily provided information to the United States Attorney's Office for the Southern District of California and the U.S. Securities and Exchange Commission ("SEC") related to its announcement that it intended to file restated financial statements for fiscal years 2011 and 2012. On June 11, 2015, the Company received a subpoena from the SEC requesting certain documents related to, among other things, the facts and circumstances surrounding the restated financial statements. The Company is providing information to the SEC in response to that subpoena and continues to cooperate with the SEC. At this stage, the Company cannot predict the ultimate outcome of this investigation or whether it will result in any loss. Accordingly, the Company has not accrued an amount for any potential loss associated with this action, but an adverse result could have a material adverse impact on its financial condition and results of operation. Federal Shareholder Derivative Matter On April 23, 2013 and May 7, 2013, two shareholder derivative actions were filed in the United States District Court for the Southern District of California, entitled Kienzle v. Schramm, et al., Case No. 13-cv-0966 (S.D. Cal. filed April 23, 2013) and Agrawal v. Cortes, et al., Case No. 13-cv-1084 (S.D. Cal. filed May 7, 2013). The complaints named as defendants certain of the Company's current and former officers and directors and named the Company as a nominal defendant. The complaints alleged that the individual defendants caused or allowed the Company to issue false and misleading statements about its financial condition, operations, management, and internal controls and falsely represented that it maintained adequate controls. The complaints asserted causes of action for breach of fiduciary duty, abuse of control, gross mismanagement, waste of corporate assets and unjust enrichment. The lawsuits sought unspecified damages, an order directing the Company to take all necessary actions to reform and improve its corporate governance and internal procedures, restitution and disgorgement of profits, benefits, and other compensation, attorneys' and experts' fees, and costs and expenses. The court issued an order consolidating the two actions on October 30, 2013 under the heading In re Maxwell Technologies, Inc. Derivative Litigation. On September 19, 2014, the parties entered into a memorandum of understanding concerning settlement of this matter related to certain corporate governance reforms to be implemented and/or maintained by the Company. On December 10, 2014, the parties signed a stipulation of settlement and on March 16, 2015, the court granted final approval of the settlement and dismissed this action. On July 13, 2015, the court issued an order establishing a fee award of $1.1 million to be paid to the plaintiffs in exchange for the benefit bestowed upon the Company due to the corporate governance reforms, and on August 10, 2015, the Company’s insurance carrier paid this amount in full. Therefore, during the quarter ended September 30, 2015, the Company released an accrued liability it has previously recorded for the $1.1 million settlement amount, as well as a previously recorded receivable from its insurance carrier of $1.1 million as the Company’s insurance carrier was expected to cover this settlement. State Shareholder Derivative Matter On April 11, 2013 and April 18, 2013, two shareholder derivative actions were filed in California Superior Court for the County of San Diego, entitled Warsh v. Schramm, et al., Case No. 37-2013-00043884 (San Diego Sup. Ct. filed April 11, 2013) and Neville v. Cortes, et al., Case No. 37-2013-00044911-CU-BT-CTL (San Diego Sup. Ct. filed April 18, 2013). The complaints named as defendants certain of the Company's current and former officers and directors as well as its former auditor McGladrey LLP. The Company was named as a nominal defendant. The complaints alleged that the individual defendants made or caused the Company to make false and/or misleading statements regarding its financial condition, and failed to disclose material adverse facts about its business, operations and prospects. The complaints asserted causes of action for breaches of fiduciary duty for disseminating false and misleading information, failing to maintain internal controls, and failing to properly oversee and manage the Company, as well as for unjust enrichment, abuse of control, gross mismanagement, professional negligence and accounting malpractice, and aiding and abetting breaches of fiduciary duty. The lawsuits sought unspecified damages, an order directing the Company to take all necessary actions to reform and improve its corporate governance and internal procedures, restitution and disgorgement of profits, benefits and other compensation, attorneys' and experts' fees, and costs and expenses. On May 7, 2013, the court consolidated the two actions. On July 2, 2013, the Company filed a motion to stay the actions pending resolution of the federal derivative actions, which the state court granted on November 1, 2013. As a result of the settlement in the federal derivative action above, the parties filed a joint stipulation to dismiss this matter and, on May 13, 2015, the Court signed an order dismissing the matter with prejudice. The deadline to appeal this order lapsed on August 24, 2015. Shareholder Inspection Letter On April 9, 2013, Stephen Neville, a purported shareholder of the Company, sent a letter to the Company seeking to inspect its books and records pursuant to California Corporations Code Section 1601. The demand sought inspection of documents related to the Company's March 7, 2013 announcement that it would be restating its previously-issued financial statements for 2011 and 2012, board minutes and committee materials, and other documents related to its board or management discussions regarding revenue recognition from January 1, 2011 to the present. Pursuant to the stipulation of settlement in the federal shareholder derivative matter and following the settlement in the federal derivative action above, the parties filed a joint stipulation to dismiss this matter and, on May 12, 2015, the Court signed an order dismissing the matter with prejudice. The deadline to appeal this order lapsed on August 24, 2015.

Legal Proceedings

Although the Company expects to incur significant legal fees in connection with the below legal proceedings, the Company is unable to estimate the amount of such legal fees and therefore, such fees will be expensed in the period the legal services are performed.

FCPA Matter

As a result of being publicly traded in the U.S., the Company is subject to the U.S. Foreign Corrupt Practices Act (“FCPA”), which prohibits companies from making improper payments to foreign officials for the purpose of obtaining or retaining business. Beginning in 2009, the Company conducted an internal review into payments made to its former independent sales agent in China with respect to sales of its high-voltage capacitor products produced by its Swiss subsidiary. In January 2011, the Company reached settlements with the SEC and the U.S. Department of Justice (“DOJ”) with respect to charges asserted by the SEC and DOJ relating to the anti-bribery, books and records, internal controls, and disclosure provisions of the FCPA and other securities laws violations. The Company paid the monetary penalties under these settlements in installments such that all monetary penalties were paid in full by January 2013. With respect to the DOJ charges, a judgment of dismissal was issued in the U.S. District Court for the Southern District of California on March 28, 2014.

On October 15, 2013, the Company received an informal notice from the DOJ that an indictment against the former Senior Vice President and General Manager of its Swiss subsidiary had been filed in the United States District Court for the Southern District of California. The indictment is against the individual, a former officer, and not against the Company and the Company does not foresee that further penalties or fines could be assessed against it as a corporate entity for this matter. However, the Company may be required throughout the term of the action to advance the legal fees and costs incurred by the individual defendant and to incur other financial obligations. While the Company maintains directors’ and officers’ insurance policies which are intended to cover legal expenses related to its indemnification obligations in situations such as these, the Company cannot determine if and to what extent the insurance policy will cover the legal fees for this matter. Accordingly, the legal fees that may be incurred by the Company in defending this former officer could have a material impact on its financial condition and results of operation.

Swiss Bribery Matter

In August 2013, the Company's Swiss subsidiary was served with a search warrant from the Swiss federal prosecutor’s office. At the end of the search, the Swiss federal prosecutor presented the Company with a listing of the materials gathered by the representatives and then removed the materials from its premises for keeping at the prosecutor’s office. Based upon the Company’s exposure to the case, the Company believes this action to be related to the same or similar facts and circumstances as the FCPA action previously settled with the SEC and the DOJ. During initial discussions, the Swiss prosecutor has acknowledged both the existence of the Company's DPA with the DOJ and its cooperation efforts thereunder, both of which should have a positive impact on discussions going forward. Additionally, other than the activities previously reviewed in conjunction with the SEC and DOJ matters under the FCPA, the Company has no reason to believe that additional facts or circumstances are under review by the Swiss authorities. In late March 2015, the Company was informed that the Swiss prosecutor intended to inform the parties in April 2015 as to whether the prosecutor’s office will bring charges or abandon the proceedings. However, to date, the Swiss prosecutor has not issued its formal decision. At this stage in the investigation, the Company is currently unable to determine the extent to which it will be subject to fines in accordance with Swiss bribery laws and what additional expenses will be incurred in order to defend this matter. As such, the Company cannot determine whether there is a reasonable possibility that a loss will be incurred nor can it estimate the range of any such potential loss. Accordingly, the Company has not accrued an amount for any potential loss associated with this action, but an adverse result could have a material adverse impact on its financial condition and results of operation.

Government Investigations

In early 2013, the Company voluntarily provided information to the United States Attorney's Office for the Southern District of California and the U.S. Securities and Exchange Commission ("SEC") related to its announcement that it intended to file restated financial statements for fiscal years 2011 and 2012. On June 11, 2015, the Company received a subpoena from the SEC requesting certain documents related to, among other things, the facts and circumstances surrounding the restated financial statements. The Company is providing information to the SEC in response to that subpoena and continues to cooperate with the SEC. At this stage, the Company cannot predict the ultimate outcome of this investigation or whether it will result in any loss. Accordingly, the Company has not accrued an amount for any potential loss associated with this action, but an adverse result could have a material adverse impact on its financial condition and results of operation.

Federal Shareholder Derivative Matter

On April 23, 2013 and May 7, 2013, two shareholder derivative actions were filed in the United States District Court for the Southern District of California, entitled Kienzle v. Schramm, et al., Case No. 13-cv-0966 (S.D. Cal. filed April 23, 2013) and Agrawal v. Cortes, et al., Case No. 13-cv-1084 (S.D. Cal. filed May 7, 2013). The complaints named as defendants certain of the Company's current and former officers and directors and named the Company as a nominal defendant. The complaints alleged that the individual defendants caused or allowed the Company to issue false and misleading statements about its financial condition, operations, management, and internal controls and falsely represented that it maintained adequate controls. The complaints asserted causes of action for breach of fiduciary duty, abuse of control, gross mismanagement, waste of corporate assets and unjust enrichment. The lawsuits sought unspecified damages, an order directing the Company to take all necessary actions to reform and improve its corporate governance and internal procedures, restitution and disgorgement of profits, benefits, and other compensation, attorneys' and experts' fees, and costs and expenses. The court issued an order consolidating the two actions on October 30, 2013 under the heading In re Maxwell Technologies, Inc. Derivative Litigation. On September 19, 2014, the parties entered into a memorandum of understanding concerning settlement of this matter related to certain corporate governance reforms to be implemented and/or maintained by the Company. On December 10, 2014, the parties signed a stipulation of settlement and on March 16, 2015, the court granted final approval of the settlement and dismissed this action. On July 13, 2015, the court issued an order establishing a fee award of $1.1 million to be paid to the plaintiffs in exchange for the benefit bestowed upon the Company due to the corporate governance reforms, and on August 10, 2015, the Company’s insurance carrier paid this amount in full. Therefore, during the quarter ended September 30, 2015, the Company released an accrued liability it has previously recorded for the $1.1 million settlement amount, as well as a previously recorded receivable from its insurance carrier of $1.1 million as the Company’s insurance carrier was expected to cover this settlement.

State Shareholder Derivative Matter

On April 11, 2013 and April 18, 2013, two shareholder derivative actions were filed in California Superior Court for the County of San Diego, entitled Warsh v. Schramm, et al., Case No. 37-2013-00043884 (San Diego Sup. Ct. filed April 11, 2013) and Neville v. Cortes, et al., Case No. 37-2013-00044911-CU-BT-CTL (San Diego Sup. Ct. filed April 18, 2013). The complaints named as defendants certain of the Company's current and former officers and directors as well as its former auditor McGladrey LLP. The Company was named as a nominal defendant. The complaints alleged that the individual defendants made or caused the Company to make false and/or misleading statements regarding its financial condition, and failed to disclose material adverse facts about its business, operations and prospects. The complaints asserted causes of action for breaches of fiduciary duty for disseminating false and misleading information, failing to maintain internal controls, and failing to properly oversee and manage the Company, as well as for unjust enrichment, abuse of control, gross mismanagement, professional negligence and accounting malpractice, and aiding and abetting breaches of fiduciary duty. The lawsuits sought unspecified damages, an order directing the Company to take all necessary actions to reform and improve its corporate governance and internal procedures, restitution and disgorgement of profits, benefits and other compensation, attorneys' and experts' fees, and costs and expenses. On May 7, 2013, the court consolidated the two actions. On July 2, 2013, the Company filed a motion to stay the actions pending resolution of the federal derivative actions, which the state court granted on November 1, 2013. As a result of the settlement in the federal derivative action above, the parties filed a joint stipulation to dismiss this matter and, on May 13, 2015, the Court signed an order dismissing the matter with prejudice. The deadline to appeal this order lapsed on August 24, 2015.

Shareholder Inspection Letter

On April 9, 2013, Stephen Neville, a purported shareholder of the Company, sent a letter to the Company seeking to inspect its books and records pursuant to California Corporations Code Section 1601. The demand sought inspection of documents related to the Company's March 7, 2013 announcement that it would be restating its previously-issued financial statements for 2011 and 2012, board minutes and committee materials, and other documents related to its board or management discussions regarding revenue recognition from January 1, 2011 to the present. Pursuant to the stipulation of settlement in the federal shareholder derivative matter and following the settlement in the federal derivative action above, the parties filed a joint stipulation to dismiss this matter and, on May 12, 2015, the Court signed an order dismissing the matter with prejudice. The deadline to appeal this order lapsed on August 24, 2015.