Debt Financing	3 Months Ended
Mar. 31, 2017
Debt Disclosure [Abstract]
Debt Financing	Debt Financing On May 9, 2016, the Company amended its existing U.S. Domestic credit facility with JPM Chase such that the financial covenants as set forth in the credit agreement would not be measured for the period ending as of March 31, 2016, and were removed in their entirety from the Facility. The credit availability under the Facility has been reduced from $15,000 to $7,000 with this amendment, and further, JPM Chase's then current Revolving Commitment under the Facility is now secured by cash held by the Company in a separate restricted use designated JPM Chase deposit account. The amount of credit available to the Company under the Facility was $7,000 from the date of the effective date of the amended facility through May 31, 2016, at which time the credit available to the Company under the Facility was reduced to $6,000 from June 1, 2016 through July 31, 2016, at which time the credit available to the Company under the Facility was reduced to $5,000 and will remain as such until the Maturity Date of the Facility on June 30, 2017. The Company intends to renew the U.S. Domestic credit facility at its maturity. During the entire period of the Facility the Company must maintain sufficient cash balances in a segregated deposit account equal to the amount of the Facility and will fully pledge such cash as collateral to the bank to support the credit available to the Company under the Facility. As of March 31, 2017 and December 31, 2016, there were no outstanding borrowings on the credit facility. At March 31, 2017 and December 31, 2016, the Company had outstanding standby letters of credit and bank guarantees totaling approximately $3,185 and $3,292, respectively, under the Facility in connection with contracts in process. Fuel Tech is committed to reimbursing the issuing bank for any payments made by the bank under these instruments. The Company pays a commitment fee of 0.25% per year on the unused portion of the revolving credit facility. At March 31, 2017 and December 31, 2016, approximately $1,815 and $1,708 was available for future borrowings under the Facility. On June 24, 2016, Beijing Fuel Tech Environmental Technologies Company, Ltd. (Beijing Fuel Tech), a wholly-owned subsidiary of Fuel Tech, entered into a new revolving credit facility (the China Facility) agreement with JPM Chase for RMB 6.5 million (approximately $943), which expires on June 23, 2017. The Company intends to renew the China Facility at its maturity. This new credit facility replaced the previous RMB 35 million facility that expired on June 24, 2016. The facility is unsecured, bears interest at a rate of 125% of the People’s Bank of China (PBOC) Base Rate, and is guaranteed by Fuel Tech. Beijing Fuel Tech can use this facility for cash advances and bank guarantees. As of March 31, 2017 and December 31, 2016, Beijing Fuel Tech had no cash borrowings under the China Facility. At March 31, 2017 and December 31, 2016, the Company had outstanding standby letters of credit and bank guarantees totaling approximately $22 and $22, respectively, on its Beijing Fuel Tech revolving credit facility in connection with contracts in process. At March 31, 2017 and December 31, 2016, approximately $921 and $914 was available for future borrowings. In the event of default on either the domestic facility or the China facility, the cross default feature in each allows the lending bank to accelerate the payments of any amounts outstanding and may, under certain circumstances, allow the bank to cancel the facility. If the Company were unable to obtain a waiver for a breach of covenant and the bank accelerated the payment of any outstanding amounts, such acceleration may cause the Company’s cash position to deteriorate or, if cash on hand were insufficient to satisfy the payment due, may require the Company to obtain alternate financing to satisfy the accelerated payment.

Debt Financing

On May 9, 2016, the Company amended its existing U.S. Domestic credit facility with JPM Chase such that the financial covenants as set forth in the credit agreement would not be measured for the period ending as of March 31, 2016, and were removed in their entirety from the Facility. The credit availability under the Facility has been reduced from $15,000 to $7,000 with this amendment, and further, JPM Chase's then current Revolving Commitment under the Facility is now secured by cash held by the Company in a separate restricted use designated JPM Chase deposit account. The amount of credit available to the Company under the Facility was $7,000 from the date of the effective date of the amended facility through May 31, 2016, at which time the credit available to the Company under the Facility was reduced to $6,000 from June 1, 2016 through July 31, 2016, at which time the credit available to the Company under the Facility was reduced to $5,000 and will remain as such until the Maturity Date of the Facility on June 30, 2017. The Company intends to renew the U.S. Domestic credit facility at its maturity. During the entire period of the Facility the Company must maintain sufficient cash balances in a segregated deposit account equal to the amount of the Facility and will fully pledge such cash as collateral to the bank to support the credit available to the Company under the Facility. As of March 31, 2017 and December 31, 2016, there were no outstanding borrowings on the credit facility.

At March 31, 2017 and December 31, 2016, the Company had outstanding standby letters of credit and bank guarantees totaling approximately $3,185 and $3,292, respectively, under the Facility in connection with contracts in process. Fuel Tech is committed to reimbursing the issuing bank for any payments made by the bank under these instruments. The Company pays a commitment fee of 0.25% per year on the unused portion of the revolving credit facility. At March 31, 2017 and December 31, 2016, approximately $1,815 and $1,708 was available for future borrowings under the Facility.

On June 24, 2016, Beijing Fuel Tech Environmental Technologies Company, Ltd. (Beijing Fuel Tech), a wholly-owned subsidiary of Fuel Tech, entered into a new revolving credit facility (the China Facility) agreement with JPM Chase for RMB 6.5 million (approximately $943), which expires on June 23, 2017. The Company intends to renew the China Facility at its maturity. This new credit facility replaced the previous RMB 35 million facility that expired on June 24, 2016. The facility is unsecured, bears interest at a rate of 125% of the People’s Bank of China (PBOC) Base Rate, and is guaranteed by Fuel Tech. Beijing Fuel Tech can use this facility for cash advances and bank guarantees. As of March 31, 2017 and December 31, 2016, Beijing Fuel Tech had no cash borrowings under the China Facility.

At March 31, 2017 and December 31, 2016, the Company had outstanding standby letters of credit and bank guarantees totaling approximately $22 and $22, respectively, on its Beijing Fuel Tech revolving credit facility in connection with contracts in process. At March 31, 2017 and December 31, 2016, approximately $921 and $914 was available for future borrowings.

In the event of default on either the domestic facility or the China facility, the cross default feature in each allows the lending bank to accelerate the payments of any amounts outstanding and may, under certain circumstances, allow the bank to cancel the facility. If the Company were unable to obtain a waiver for a breach of covenant and the bank accelerated the payment of any outstanding amounts, such acceleration may cause the Company’s cash position to deteriorate or, if cash on hand were insufficient to satisfy the payment due, may require the Company to obtain alternate financing to satisfy the accelerated payment.