Subsequent Events	12 Months Ended
Oct. 01, 2016
Subsequent Events [Abstract]
Subsequent Events	16. SUBSEQUENT EVENTS Acquisition of Rofin On November 7, 2016, we completed our previously announced acquisition of Rofin pursuant to the Merger Agreement dated March 16, 2016. Rofin is one of the world's leading developers and manufacturers of high-performance industrial laser sources and laser-based solutions and components. As a condition of the acquisition, we are required to divest ourselves of Rofin’s low power CO2 laser business based in Hull, United Kingdom, and will report this business separately as a discontinued operation until it is divested. The acquisition was an all-cash transaction at a price of $32.50 per share of Rofin common stock. The aggregate consideration paid by us to the former Rofin stockholders was approximately $904.5 million, excluding related transaction fees and expenses. We also paid $15.3 million due to the cancellation of options held by employees of Rofin. We funded the payment of the aggregate consideration with a combination of our available cash on hand and the proceeds from the Euro Term Loan described below. We are in the process of evaluating the business combination accounting considerations, including the consideration transferred and the initial purchase price allocation. Execution of the Credit Agreement On November 7, 2016, we entered into the Credit Agreement by and among us, Coherent Holding GmbH, as borrower (the “Borrower”), and certain of our direct and indirect subsidiaries from time to time party thereto, as guarantors, the lenders from time to time party thereto, Barclays Bank PLC, as administrative agent and L/C Issuer, Bank of America, N.A., as L/C Issuer, and The Bank of Tokyo-Mitsubishi UFJ, Ltd., as L/C Issuer. The Credit Agreement provided for a 670.0 million Euro senior secured term loan facility and a $100.0 million senior secured revolving credit facility with a $30.0 million letter of credit sublimit and a $10.0 million swing line sublimit. We may increase the aggregate revolving commitments or borrow incremental term loans in an aggregate principal amount of up to $150.0 million, subject to certain conditions, including obtaining additional commitments from the lenders then party to the Credit Agreement or new lenders. On November 7, 2016, we borrowed the full 670.0 million Euros under the Euro Term Loan and its proceeds were used to finance the acquisition of Rofin and pay related fees and expenses. Also, on November 7, 2016, we used 10.0 million Euro of the capacity under the Revolving Credit Facility for the issuance of a letter of credit. We expect to use future loans under the Revolving Credit Facility, if any, for general corporate purposes. The Credit Agreement replaces our existing $50.0 million Credit Agreement with Union Bank of California. The terms of the Credit Agreement require Borrower to prepay the term loans in certain circumstances, including from excess cash flow beyond a threshold amount, from the receipt of proceeds from certain dispositions or from the incurrence of certain indebtedness, and from extraordinary receipts resulting in net cash proceeds in excess of $10 million in any fiscal year. Borrower has the right to prepay loans under the Credit Agreement in whole or in part at any time without premium or penalty. Revolving loans may be borrowed, repaid and reborrowed until the fifth anniversary of the Closing Date, at which time all outstanding revolving loans must be repaid. The Euro Term Loan matures on the seventh anniversary of the Closing Date, at which time all outstanding principal and accrued and unpaid interest on the Euro Term Loan must be repaid. Loans under the Credit Agreement bear interest, at the Borrower’s option, at a rate equal to either (i) the London interbank offered rate (the “Eurocurrency Rate”) or (ii) a base rate (the “Base Rate”) equal to the highest of (x) the federal funds rate, plus 0.50%, (y) the prime rate then in effect and (z) the Eurocurrency Rate for loans denominated in U.S. dollars applicable to a one-month interest period, plus 1.0%, in each case, plus an applicable margin. The applicable margin for term loans borrowed as Eurocurrency Rate loans, is 3.50% initially, and following the first anniversary of the Closing Date ranges from 3.00% to 3.50% depending on the consolidated total gross leverage ratio at the time of determination. For term loans borrowed as Base Rate Loans, the applicable margin initially is 2.50%, and following the first anniversary of the Closing Date ranges from 2.00% to 2.50% depending upon the consolidated total gross leverage ratio at the time of determination. The applicable margin for revolving loans borrowed as Eurocurrency Rate Loans, ranges from 3.75% to 4.25%, and for revolving loans borrowed as Base Rate Loans, ranges from 2.75% to 3.25%, in each case, based on the consolidated total gross leverage ratio at the time of determination. Interest on Base Rate Loans is payable quarterly in arrears. Interest on Eurocurrency Rate Loans is payable at the end of the applicable interest period. Interest periods for Eurocurrency Rate loans may be, at the Borrower’s option, one, two, three or six months. The Credit Agreement requires the Borrower to make scheduled quarterly payments on the Euro Term Loan of 0.25% of the original principal amount of the Euro Term Loan, with any remaining principal payable at maturity. A commitment fee accrues on any unused portion of the revolving loan commitments under the Credit Agreement at a rate of 0.375% or 0.5% depending on the consolidated total gross leverage ratio at any time of determination. The Borrower is also obligated to pay other customary fees for a credit facility of this size and type. On the Closing Date, we and certain of our direct and indirect subsidiaries, as guarantors, provided an unconditional guaranty of all obligations of the Borrower and the other loan parties arising under the Credit Agreement, the other loan documents and under swap contracts and treasury management agreements with the lenders or their affiliates (with certain limited exceptions). The Borrower and the guarantors have also granted security interests in substantially all their assets to secure such obligations. The Credit Agreement contains customary affirmative covenants, including covenants regarding the payment of taxes and other obligations, maintenance of insurance, reporting requirements and compliance with applicable laws and regulations, and negative covenants, including covenants limiting the ability of us and our subsidiaries to, among other things, incur debt, grant liens, make investments, make certain restricted payments, transact with affiliates, and sell assets. The Credit Agreement also requires us and our subsidiaries to maintain a senior secured net leverage ratio as of the last day of each fiscal quarter of less of than or equal to 3.50 to 1.00. The Credit Agreement contains customary events of default that include, among other things, payment defaults, cross defaults with certain other indebtedness, violation of covenants, inaccuracy of representations and warranties in any material respect, change in control of us and the Borrower, judgment defaults, and bankruptcy and insolvency events. If an event of default exists, the lenders may require the immediate payment of all Obligations, as defined in the Credit Agreement, and may exercise certain other rights and remedies provided for under the Credit Agreement, the other loan documents and applicable law. The acceleration of such obligations is automatic upon the occurrence of a bankruptcy and insolvency event of default. Segment Restatement As a result of the acquisition of Rofin, and subsequent to fiscal 2016 year-end, we announced that in the first quarter of fiscal 2017 we will reorganize our existing two segments into two new reporting segments for the combined company, OEM Laser Systems and Industrial Lasers and Systems. Accordingly, our segment information will be restated retroactively in the first quarter of fiscal 2017.

16. SUBSEQUENT EVENTS

Acquisition of Rofin

On November 7, 2016, we completed our previously announced acquisition of Rofin pursuant to the Merger Agreement dated March 16, 2016. Rofin is one of the world's leading developers and manufacturers of high-performance industrial laser sources and laser-based solutions and components. As a condition of the acquisition, we are required to divest ourselves of Rofin’s low power CO2 laser business based in Hull, United Kingdom, and will report this business separately as a discontinued operation until it is divested. The acquisition was an all-cash transaction at a price of $32.50 per share of Rofin common stock. The aggregate consideration paid by us to the former Rofin stockholders was approximately $904.5 million, excluding related transaction fees and expenses. We also paid $15.3 million due to the cancellation of options held by employees of Rofin. We funded the payment of the aggregate consideration with a combination of our available cash on hand and the proceeds from the Euro Term Loan described below. We are in the process of evaluating the business combination accounting considerations, including the consideration transferred and the initial purchase price allocation.

Execution of the Credit Agreement

On November 7, 2016, we entered into the Credit Agreement by and among us, Coherent Holding GmbH, as borrower (the “Borrower”), and certain of our direct and indirect subsidiaries from time to time party thereto, as guarantors, the lenders from time to time party thereto, Barclays Bank PLC, as administrative agent and L/C Issuer, Bank of America, N.A., as L/C Issuer, and The Bank of Tokyo-Mitsubishi UFJ, Ltd., as L/C Issuer. The Credit Agreement provided for a 670.0 million Euro senior secured term loan facility and a $100.0 million senior secured revolving credit facility with a $30.0 million letter of credit sublimit and a $10.0 million swing line sublimit. We may increase the aggregate revolving commitments or borrow incremental term loans in an aggregate principal amount of up to $150.0 million, subject to certain conditions, including obtaining additional commitments from the lenders then party to the Credit Agreement or new lenders. On November 7, 2016, we borrowed the full 670.0 million Euros under the Euro Term Loan and its proceeds were used to finance the acquisition of Rofin and pay related fees and expenses. Also, on November 7, 2016, we used 10.0 million Euro of the capacity under the Revolving Credit Facility for the issuance of a letter of credit. We expect to use future loans under the Revolving Credit Facility, if any, for general corporate purposes. The Credit Agreement replaces our existing $50.0 million Credit Agreement with Union Bank of California.

The terms of the Credit Agreement require Borrower to prepay the term loans in certain circumstances, including from excess cash flow beyond a threshold amount, from the receipt of proceeds from certain dispositions or from the incurrence of certain indebtedness, and from extraordinary receipts resulting in net cash proceeds in excess of $10 million in any fiscal year. Borrower has the right to prepay loans under the Credit Agreement in whole or in part at any time without premium or penalty. Revolving loans may be borrowed, repaid and reborrowed until the fifth anniversary of the Closing Date, at which time all outstanding revolving loans must be repaid. The Euro Term Loan matures on the seventh anniversary of the Closing Date, at which time all outstanding principal and accrued and unpaid interest on the Euro Term Loan must be repaid.

Loans under the Credit Agreement bear interest, at the Borrower’s option, at a rate equal to either (i) the London interbank offered rate (the “Eurocurrency Rate”) or (ii) a base rate (the “Base Rate”) equal to the highest of (x) the federal funds rate, plus 0.50%, (y) the prime rate then in effect and (z) the Eurocurrency Rate for loans denominated in U.S. dollars applicable to a one-month interest period, plus 1.0%, in each case, plus an applicable margin. The applicable margin for term loans borrowed as Eurocurrency Rate loans, is 3.50% initially, and following the first anniversary of the Closing Date ranges from 3.00% to 3.50% depending on the consolidated total gross leverage ratio at the time of determination. For term loans borrowed as Base Rate Loans, the applicable margin initially is 2.50%, and following the first anniversary of the Closing Date ranges from 2.00% to 2.50% depending upon the consolidated total gross leverage ratio at the time of determination. The applicable margin for revolving loans borrowed as Eurocurrency Rate Loans, ranges from 3.75% to 4.25%, and for revolving loans borrowed as Base Rate Loans, ranges from 2.75% to 3.25%, in each case, based on the consolidated total gross leverage ratio at the time of determination. Interest on Base Rate Loans is payable quarterly in arrears. Interest on Eurocurrency Rate Loans is payable at the end of the applicable interest period. Interest periods for Eurocurrency Rate loans may be, at the Borrower’s option, one, two, three or six months.

The Credit Agreement requires the Borrower to make scheduled quarterly payments on the Euro Term Loan of 0.25% of the original principal amount of the Euro Term Loan, with any remaining principal payable at maturity. A commitment fee accrues on any unused portion of the revolving loan commitments under the Credit Agreement at a rate of 0.375% or 0.5% depending on the consolidated total gross leverage ratio at any time of determination. The Borrower is also obligated to pay other customary fees for a credit facility of this size and type.

On the Closing Date, we and certain of our direct and indirect subsidiaries, as guarantors, provided an unconditional guaranty of all obligations of the Borrower and the other loan parties arising under the Credit Agreement, the other loan documents and under swap contracts and treasury management agreements with the lenders or their affiliates (with certain limited exceptions). The Borrower and the guarantors have also granted security interests in substantially all their assets to secure such obligations.

The Credit Agreement contains customary affirmative covenants, including covenants regarding the payment of taxes and other obligations, maintenance of insurance, reporting requirements and compliance with applicable laws and regulations, and negative covenants, including covenants limiting the ability of us and our subsidiaries to, among other things, incur debt, grant liens, make investments, make certain restricted payments, transact with affiliates, and sell assets. The Credit Agreement also requires us and our subsidiaries to maintain a senior secured net leverage ratio as of the last day of each fiscal quarter of less of than or equal to 3.50 to 1.00. The Credit Agreement contains customary events of default that include, among other things, payment defaults, cross defaults with certain other indebtedness, violation of covenants, inaccuracy of representations and warranties in any material respect, change in control of us and the Borrower, judgment defaults, and bankruptcy and insolvency events. If an event of default exists, the lenders may require the immediate payment of all Obligations, as defined in the Credit Agreement, and may exercise certain other rights and remedies provided for under the Credit Agreement, the other loan documents and applicable law. The acceleration of such obligations is automatic upon the occurrence of a bankruptcy and insolvency event of default.

Segment Restatement

As a result of the acquisition of Rofin, and subsequent to fiscal 2016 year-end, we announced that in the first quarter of fiscal 2017 we will reorganize our existing two segments into two new reporting segments for the combined company, OEM Laser Systems and Industrial Lasers and Systems. Accordingly, our segment information will be restated retroactively in the first quarter of fiscal 2017.