Nature of operations, basis of presentation and recently issues accounting pronouncements (Policies)	9 Months Ended
	Sep. 30, 2016
Organization Consolidation Basis Of Presentation Business Description And Accounting Policies [Abstract]
Basis of presentation	Basis of presentation The accompanying unaudited condensed consolidated financial statements have been prepared in accordance with generally accepted accounting principles in the United States (“U.S. GAAP”) for interim financial information and with the instructions to Form 10-Q and Rule 10-01 of Regulation S-X. Pursuant to these rules and regulations, certain information and note disclosures normally included in financial statements prepared in accordance with U.S. GAAP have been condensed or omitted. In the opinion of management, all adjustments (consisting of normal recurring items) considered necessary for a fair statement have been included. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and related notes contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2015 (the “2015 Form 10-K”). Operating results for the three and nine months ended September 30, 2016, are not necessarily indicative of the results that may be expected for other interim periods or the year ending December 31, 2016. The balance sheet at December 31, 2015, has been derived from the audited financial statements at that date, but does not include all of the information and footnotes required by U.S. GAAP for complete financial statements. The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. On an ongoing basis, the Company evaluates its estimates including those related to revenue recognition, contractual allowances, doubtful accounts, inventories, potential goodwill and intangible asset impairment, fair value measurements, litigation and contingent liabilities, income taxes, and shared-based compensation. Actual results could differ from these estimates. As permitted under U.S. GAAP, interim accounting for certain expenses, including income taxes, is based on full year forecasts.
Change in accounting principle for goodwill	Change in accounting principle for goodwill During the quarter ended September 30, 2016, the Company voluntarily changed its annual goodwill testing date from the end of the fourth quarter, December 31, to the beginning of the fourth quarter, October 1. The Company believes this change in the method of applying the accounting principle is preferable, as it will more closely align the annual impairment testing date with the most current information from the budgeting and strategic planning process and will provide management with additional time to complete its annual assessment in advance of our year-end reporting. The change will not delay, accelerate or avoid an impairment charge. This change is not applied retrospectively, as it is impracticable to do so because retrospective application would require application of significant estimates and assumptions with the use of hindsight. Accordingly, the change will be applied prospectively.
Recently adopted accounting standard	Recently adopted accounting standard In March 2016, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2016-09, Improvements to Employee Share-Based Payment Accounting. This ASU simplifies several aspects of the accounting for share-based payment transactions, including the income tax consequences, accounting for forfeitures, and classification on the statement of cash flows. During the quarter ended September 30, 2016, the Company early adopted this new accounting standard with an effective date of January 1, 2016. Under the new standard, all excess tax benefits and tax deficiencies will be recognized as income tax expense or benefit in the income statement as discrete items in the reporting period in which they occur. The Company has applied guidance related to the classification of excess tax benefits on the statement of cash flows on a retrospective basis. Additionally, the Company has elected to account for forfeitures as they occur and recorded the impact of such change on previously reported periods through a $1.4 cumulative-effect adjustment to retained earnings as of January 1, 2016. Further, the Company has applied the guidance for employee taxes paid to tax authorities when shares are withheld to satisfy the employer’s statutory income tax withholding obligation on a retrospective basis. The adoption resulted in a $0.3 million decrease in net cash provided by financing activities and a $0.3 million increase in net cash from operating activities for the nine months ended September 30, 2015. The adoption did not have a material impact on the Company’s consolidated statement of operations and comprehensive income (loss) for the three and nine month periods ended September 30, 2016.
Recently issued accounting pronouncements	Recently issued accounting pronouncements In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). ASU 2014-09 supersedes the revenue recognition requirements in Revenue Recognition (Topic 605), and requires entities to recognize revenue in a way that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. As currently amended, the standard is effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period, with early adoption permitted. The standard is to be applied either retrospectively or as a cumulative effect adjustment as of the adoption date. The Company is currently evaluating the effect that adopting this new accounting guidance will have on the consolidated results of operations, cash flows, and financial position and developing processes and procedures to implement this guidance. In July 2015, the FASB issued ASU 2015-11, Simplifying the Measurement of Inventory. This ASU requires that an entity should measure inventory at the lower of cost and net realizable value. Net realizable value is the estimated selling price in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The guidance will be effective prospectively for interim and annual periods beginning after December 15, 2016, with early adoption permitted. The Company is currently evaluating the new guidance and does not expect it will have a material impact on its consolidated financial statements. In January 2016, the FASB issued ASU 2016-01, Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities. This ASU amends various aspects of the recognition, measurement, presentation, and disclosure for certain financial instruments. The guidance will be effective prospectively for annual periods beginning after December 15, 2017, including interim periods within those fiscal years with early adoption permitted. The Company is currently evaluating the new guidance and does not expect it will have a material impact on its consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842). This ASU requires that a lessee recognize lease assets and lease liabilities for those leases classified as operating leases. The guidance is effective for interim and annual periods beginning after December 15, 2018, and will be applied at the beginning of the earliest period presented using a modified retrospective approach. The Company is currently evaluating the impact this ASU may have on its consolidated financial statements. In October 2016, the FASB issued ASU 2016-16, Intra-Entity Transfers of Assets Other Than Inventory. This ASU reduces the complexity in the accounting standards by allowing the recognition of current and deferred income taxes for an intra-entity asset transfer, other than inventory, when the transfer occurs. The guidance will be effective for annual periods beginning after December 15, 2017, including interim periods within those fiscal years with early adoption permitted, and is to be applied using a modified retrospective approach. The Company is currently evaluating the impact this ASU may have on its consolidated financial statements.