Fair Value Measurement of Financial Instruments	12 Months Ended
Fair Value Measurement of Financial Instruments	Dec. 31, 2018
Fair Value Measurement of Financial Instruments
Fair Value Measurement of Financial Instruments	13. Fair Value Measurement of Financial Instruments The Company’s assets measured at fair value on a nonrecurring basis include long-lived assets. The Company reviews the carrying amounts of such assets when events indicate that their carrying amounts may not be recoverable. Any resulting asset impairment would require that the asset be recorded at its fair value. The resulting fair value measurements of the assets are considered to be Level 3 inputs. Long-lived assets, primarily comprised of property and equipment, held and used with a carrying amount of zero and $0.2 million were fully impaired during the years ended December 31, 2018 and 2017, respectively. The carrying value of the Convertible Notes at December 31, 2018 was $36.2 million which approximates their fair value at December 31, 2018. The Company estimates the fair value of the Convertible Notes using commonly accepted valuation methodologies and unobservable inputs based on the low volume of similar market activity (Level 3). The Company carries the Convertible Notes at face value less unamortized debt discount and issuance costs on its condensed consolidated balance sheets. For further information on the Convertible Notes, see “Note 12—Debt".

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.