Commitments and contingencies	9 Months Ended
Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and contingencies	Commitments and contingencies Inventory The Company enters into various inventory-related purchase agreements with suppliers. Generally, under these agreements, 100% of orders are cancelable by giving notice 29 days prior to the expected shipment date. Orders are non-cancelable within 28 days prior to the expected shipment date. At June 30, 2018, the Company had $40.9 million in non-cancelable purchase commitments with inventory suppliers. The remaining minimum total purchase commitments under the agreements with these suppliers at June 30, 2018 was $38.9 million for the remainder of fiscal 2018 and $2.0 million in fiscal 2019. Legal proceedings From time to time, the Company is involved in legal proceedings in the ordinary course of business, including claims relating to employee relations, business practices and patent infringement. Litigation can be expensive and disruptive to normal business operations. Moreover, the results of complex legal proceedings are difficult to predict and the Company’s view of these matters may change in the future as the litigation and events related thereto unfold. The Company expenses legal fees as incurred. The Company records a provision for contingent losses when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. An unfavorable outcome to any legal matter, if material, could have an adverse effect on the Company’s operations or its financial position, liquidity or results of operations. On October 21, 2014, the Company commenced a patent infringement action in the United States District Court, District of Delaware against D&M Holdings Inc. d/b/a The D+M Group, D&M Holdings U.S. Inc. and Denon Electronics (USA), LLC (collectively, “Denon”). On May 18, 2018, the Company entered into a patent covenant agreement with Denon, effective May 17, 2018, with a term lasting through May 22, 2022. Under the agreement, Denon will make royalty payments over the nine months following the effective date, covering both historical sales and sales throughout the term, at an effective royalty rate materially consistent with the December 14, 2017 jury verdict. Pursuant to the agreement, all claims asserted in the Company’s patent infringement claim against Denon and in Denon’s countersuit against the Company were dismissed with prejudice and the parties released claims of any past infringement of the patents asserted in the litigation between the Company and Denon and any patents related thereto. On March 10, 2017, Implicit, LLC (“Implicit”) filed a patent infringement action in the United States District Court, District of Delaware against the Company. Implicit is asserting that the Company infringed on two patents in this case. The Company denies the allegations. There is no assurance of a favorable outcome and the Company’s business could be adversely affected as a result of a finding that the Company patents-in-suit are invalid and/or unenforceable. A range of loss, if any, associated with this matter is not probable or reasonably estimable as of June 30, 2018 and September 30, 2017. The Company is involved in certain other litigation matters not listed above but does not consider the matters to be material either individually or in the aggregate at this time. The Company’s view of the matters not listed may change in the future as the litigation and events related thereto unfold.

Commitments and contingencies

Inventory

The Company enters into various inventory-related purchase agreements with suppliers. Generally, under these agreements, 100% of orders are cancelable by giving notice 29 days prior to the expected shipment date. Orders are non-cancelable within 28 days prior to the expected shipment date. At June 30, 2018, the Company had $40.9 million in non-cancelable purchase commitments with inventory suppliers. The remaining minimum total purchase commitments under the agreements with these suppliers at June 30, 2018 was $38.9 million for the remainder of fiscal 2018 and $2.0 million in fiscal 2019.

Legal proceedings

From time to time, the Company is involved in legal proceedings in the ordinary course of business, including claims relating to employee relations, business practices and patent infringement. Litigation can be expensive and disruptive to normal business operations. Moreover, the results of complex legal proceedings are difficult to predict and the Company’s view of these matters may change in the future as the litigation and events related thereto unfold. The Company expenses legal fees as incurred. The Company records a provision for contingent losses when it is both probable that a liability has been incurred and the amount of the loss can be reasonably estimated. An unfavorable outcome to any legal matter, if material, could have an adverse effect on the Company’s operations or its financial position, liquidity or results of operations.

On October 21, 2014, the Company commenced a patent infringement action in the United States District Court, District of Delaware against D&M Holdings Inc. d/b/a The D+M Group, D&M Holdings U.S. Inc. and Denon Electronics (USA), LLC (collectively, “Denon”). On May 18, 2018, the Company entered into a patent covenant agreement with Denon, effective May 17, 2018, with a term lasting through May 22, 2022. Under the agreement, Denon will make royalty payments over the nine months following the effective date, covering both historical sales and sales throughout the term, at an effective royalty rate materially consistent with the December 14, 2017 jury verdict. Pursuant to the agreement, all claims asserted in the Company’s patent infringement claim against Denon and in Denon’s countersuit against the Company were dismissed with prejudice and the parties released claims of any past infringement of the patents asserted in the litigation between the Company and Denon and any patents related thereto.

On March 10, 2017, Implicit, LLC (“Implicit”) filed a patent infringement action in the United States District Court, District of Delaware against the Company. Implicit is asserting that the Company infringed on two patents in this case. The Company denies the allegations. There is no assurance of a favorable outcome and the Company’s business could be adversely affected as a result of a finding that the Company patents-in-suit are invalid and/or unenforceable. A range of loss, if any, associated with this matter is not probable or reasonably estimable as of June 30, 2018 and September 30, 2017.

The Company is involved in certain other litigation matters not listed above but does not consider the matters to be material either individually or in the aggregate at this time. The Company’s view of the matters not listed may change in the future as the litigation and events related thereto unfold.