Company Operations and Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
Accounting Policies [Abstract]
Consolidation	Consolidation—The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries. All significant intercompany accounts and transactions have been eliminated.
Cash and Cash Equivalents	Cash and Cash Equivalents—The Company considers cash equivalents to be highly liquid investments with a maturity at the date of purchase of three months or less. The Company invests its cash equivalents primarily in money market funds with high quality institutions.
Accounts Receivable	Accounts Receivable—The Company sells its products directly to hospitals and reference laboratories as well as to distributors in the U.S. and sells directly to hospitals and labs and through distribution internationally (see Note 9). The Company periodically assesses the financial strength of these customers and establishes reserves for anticipated losses when necessary, which historically have not been material. The Company’s reserves primarily consist of amounts related to cash discounts and contract rebates. The balance of accounts receivable is net of reserves of $12.0 million and $12.3 million at December 31, 2018 and 2017, respectively.
Concentration of Credit Risk	Concentration of Credit Risk—Financial instruments that potentially subject the Company to significant concentrations of credit risk consists principally of trade accounts receivable. The Company performs credit evaluations of its customers’ financial condition and limits the amount of credit extended when deemed necessary, but generally requires no collateral. Credit quality is monitored regularly by reviewing credit history. The Company believes that the concentration of credit risk in its trade accounts receivables is moderated by its credit evaluation process, relatively short collection terms, the high level of credit worthiness of its customers, and letters of credit issued on the Company’s behalf. Potential credit losses are limited to the gross value of accounts receivable.
Inventories	Inventories—Inventories are stated at the lower of cost (first-in, first-out) or net realizable value. The Company reviews the components of its inventory on a quarterly basis for excess, obsolete and impaired inventory and makes appropriate dispositions as obsolete stock is identified.
Property, Plant and Equipment	Property, Plant and Equipment—Property, plant and equipment is recorded at cost and depreciated over the estimated useful lives of the assets (three to fifteen years) using the straight-line method. Amortization of leasehold improvements is computed on the straight-line method over the estimated useful lives of the assets.
Intangible Assets	Goodwill and Intangible Assets—Intangible assets are recorded at cost and amortized on a straight-line basis over their estimated useful lives, except for indefinite-lived intangibles such as goodwill. Software development costs associated with software to be leased or otherwise marketed are expensed as incurred until technological feasibility has been established. After technological feasibility is established, software development costs are capitalized. The capitalized cost is amortized on a straight-line basis over the estimated product life or on the ratio of current revenues to total projected product revenues, whichever is greater.
Convertible Debt	Convertible Debt—The Company accounts for convertible debt instruments that may be settled in cash upon conversion (including combination settlement of cash equal to the “principal portion” and delivery of the “share amount” in excess of the conversion value over the principal portion in shares of common stock and/or cash) by separating the liability and equity components of the instruments in a manner that reflects our nonconvertible debt borrowing rate. The Company determines the carrying amount of the liability component by measuring the fair value of similar debt instruments that do not have the conversion feature. If no similar debt instrument exists, the Company estimates fair value by using assumptions that market participants would use in pricing a debt instrument, including market interest rates, credit standing, yield curves and volatilities. Determining the fair value of the debt component requires the use of accounting estimates and assumptions. These estimates and assumptions are judgmental in nature and could have a significant impact on the determination of the debt component, and the associated non-cash interest expense. See Note 3 for additional discussion of the Convertible Senior Notes issued in December 2014.
Revenue Recognition	Revenue Recognition
Research and Development Costs	Research and Development Costs—Research and development costs are charged to operations as incurred. In conjunction with certain third-party service agreements, the Company is required to make periodic payments based on achievement of certain milestones. The costs related to these research and development services are also charged to operations as incurred.
Shipping and Handling Cost, Policy [Policy Text Block]	Product Shipment Costs—Product shipment costs are included in sales and marketing expense in the accompanying Consolidated Statements of Operations.
Advertising Costs	Advertising Costs—Advertising costs are expensed as incurred.
Deferred Rent	Deferred Rent—The Company enters into lease arrangements for office space under non-cancelable operating leases. Certain of the operating lease agreements contain rent escalation provisions, which are considered in determining the straight-line rent expense to be recorded over the lease term. The lease term begins on the date of initial possession of the leased property for purposes of recognizing lease expense on a straight-line basis over the term of the lease. The Company does not assume renewals in the determination of the lease term unless the renewals are deemed to be reasonably assured at lease inception. The difference between rent expense and amounts paid under the Company’s lease agreements are recorded as deferred rent.
Income Taxes	Income Taxes—Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes, using enacted tax rates in effect for the year in which the differences are expected to reverse. Valuation allowances are established, when necessary, to reduce deferred tax assets to the amount expected to be realized. The Company’s policy is to recognize the interest expense and penalties related to income tax matters as a component of the income tax provision.
Fair Value of Financial Instruments	Fair Value of Financial Instruments—
Product Warranty	Product Warranty—The Company generally sells products with a limited product warranty and certain limited indemnifications. Due to product testing, the short time between product shipment and the detection and correction of product failures and a low historical rate of payments on claims, the historical activity and the related expense were not significant for the fiscal years presented.
Stock-Based Compensation	Stock-Based Compensation—Compensation expense related to stock options granted is recognized ratably over the service vesting period for the entire option. For stock options with graded vesting, the Company ensures that the cumulative amount of compensation expense recognized at the end of any reporting period at least equals the portion of the stock option that has vested at that date. The total number of stock options expected to vest is adjusted by estimated forfeiture rates. The Company determined the estimated fair value of each stock option on the date of grant using the Black-Scholes option valuation model. The fair value of restricted stock units is determined based on the closing market price of the Company’s common stock on the grant date.
Comprehensive (Loss) Income	Comprehensive Income (loss)—Comprehensive income (loss) includes unrealized gains and losses which are related to the cumulative translation adjustments excluded from the Company’s Consolidated Statements of Operations.
Use of Estimates	Use of Estimates—The preparation of financial statements in conformity with accounting principles generally accepted in the U.S. requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.
Accounting Periods	Accounting Periods—Each of the Company’s fiscal quarters end on the Sunday closest to the end of the calendar quarter. The Company’s fiscal year ends are December 30, 2018, December 31, 2017 and January 1, 2017. For ease of reference, the calendar quarter end dates are used herein.
Lessee, Operating Leases [Text Block]	In February 2016, the FASB issued guidance codified in ASU 2016-02 (Topic 842), Leases. The guidance requires a lessee to recognize a lease liability for the obligation to make lease payments and a right-of-use asset representing the right to use the underlying asset for the lease term on the balance sheet. Under ASU 2016-02, adoption was required on a modified retrospective transition basis for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. In July 2018, the FASB issued ASU 2018-11, which allows for an alternative method to adopt the lease standard by recognizing a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption, with no adjustment to prior comparative periods. ASU 2016-02 and all subsequent amendments (collectively, “ASC 842”) are effective for public entities for annual reporting periods beginning after December 15, 2018, including interim periods therein. The Company will adopt ASC 842 on January 1, 2019 using the alternative method of adoption. We estimate that the impact of the adoption will be to add approximately $87.0 million in operating right-of-use assets; increase the current portion of operating lease liabilities and non-current operating lease liabilities by approximately $5.0 million and $85.0 million, respectively; and decrease current and non-current deferred rent by approximately $0.5 million and $2.5 million, respectively. There are no adjustments to retained earnings. In applying ASC 842, the Company will adopt the package of practical expedients which, among other things, allows the Company to carry forward its historical lease classification. Additionally, the Company will adopt a policy to exclude short-term leases from the calculation of the right-of-use assets and lease liabilities.
Recent Accounting Pronouncements	Recent Accounting Pronouncements—In May 2014, the Financial Accounting Standards Board (“FASB”) issued guidance codified in Accounting Standards Update (“ASU”) 2014-09, Revenue from Contracts with Customers, which amends the guidance in former ASC 605, Revenue Recognition (“ASU 2014-09”). The standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. In doing so, companies are required to use more judgment and make more estimates than under prior authoritative guidance. These may include identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. The FASB has issued several amendments to the new standard, which include clarification of accounting guidance related to identification of performance obligations, intellectual property licenses and principal vs. agent considerations. ASU 2014-09 and all subsequent amendments (collectively, “ASC 606”) were effective for public entities for annual reporting periods beginning after December 15, 2017, including interim periods therein. The Company adopted ASC 606 on January 1, 2018, using the modified retrospective transition method applied to those contracts which were not completed as of that date. The cumulative effect of applying the new revenue standard to all incomplete contracts as of January 1, 2018 was not material and, therefore, did not result in an adjustment to opening retained earnings. The adoption of ASC 606 did not have a material impact on the Company’s consolidated financial position, results of operations, equity or cash flows as of the adoption date or for the year ended December 31, 2018. In February 2016, the FASB issued guidance codified in ASU 2016-02 (Topic 842), Leases. The guidance requires a lessee to recognize a lease liability for the obligation to make lease payments and a right-of-use asset representing the right to use the underlying asset for the lease term on the balance sheet. Under ASU 2016-02, adoption was required on a modified retrospective transition basis for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. In July 2018, the FASB issued ASU 2018-11, which allows for an alternative method to adopt the lease standard by recognizing a cumulative-effect adjustment to the opening balance of retained earnings in the period of adoption, with no adjustment to prior comparative periods. ASU 2016-02 and all subsequent amendments (collectively, “ASC 842”) are effective for public entities for annual reporting periods beginning after December 15, 2018, including interim periods therein. The Company will adopt ASC 842 on January 1, 2019 using the alternative method of adoption. We estimate that the impact of the adoption will be to add approximately $87.0 million in operating right-of-use assets; increase the current portion of operating lease liabilities and non-current operating lease liabilities by approximately $5.0 million and $85.0 million, respectively; and decrease current and non-current deferred rent by approximately $0.5 million and $2.5 million, respectively. There are no adjustments to retained earnings. In applying ASC 842, the Company will adopt the package of practical expedients which, among other things, allows the Company to carry forward its historical lease classification. Additionally, the Company will adopt a policy to exclude short-term leases from the calculation of the right-of-use assets and lease liabilities. In January 2017, the FASB issued guidance codified in ASU 2017-04, Intangibles-Goodwill and Other (Topic 350) Simplifying the Test for Goodwill Impairment (“ASU 2017-04”). Under this new guidance, an entity will no longer determine goodwill impairment by calculating the implied fair value of goodwill by assigning the fair value of a reporting unit to all of its assets and liabilities as if that reporting unit had been acquired in a business combination. Instead, an entity will compare the fair value of a reporting unit with its carrying amount and recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value. The guidance is effective for fiscal years beginning after December 15, 2019 including interim periods therein. The Company is currently evaluating the impact of this guidance and expects to adopt the standard in the first quarter of 2020.