Summary of Significant Accounting Policies

The Company’s significant accounting policies are described in Note 2 to its audited consolidated financial statements for the year ended December 31, 2013, which are included in the Company’s Annual Report on Form 10-K that was filed with the SEC on March 20, 2014. Except as discussed below, these accounting policies have not significantly changed during the six months ended June 30, 2014.

Restricted Cash

In March 2014, the Company borrowed and set aside cash for the payment of a portion of the Orthotec litigation settlement (see Note 6) as limited by the terms of the facility agreement that we entered into with Deerfield on March 17, 2014 (see Note 5). The Company classified this cash as restricted, because it may not be used for purposes other than payments of amounts due under the Orthotec litigation settlement agreement.

Fair Value Measurements

The carrying amount of financial instruments consisting of cash, restricted cash, trade accounts receivable, prepaid expenses and other current assets, accounts payable, accrued expenses, accrued compensation and current portion of long-term debt included in the Company’s consolidated financial statements are reasonable estimates of fair value due to their short maturities. Based on the borrowing rates currently available to the Company for loans with similar terms, management believes the fair value of long-term debt approximates its carrying value.

Authoritative guidance establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows:



Level 1:	Observable inputs such as quoted prices in active markets;
Level 2:	Inputs, other than the quoted prices in active markets, that are observable either directly or indirectly; and
Level 3:	Unobservable inputs in which there is little or no market data, which require the reporting entity to develop its own assumptions.

The Company does not maintain any financial instruments that are considered to be Level 1 or Level 2 instruments as of June 30, 2014 or December 31, 2013. The Company classifies its common stock warrant liabilities within Level 3 of the fair value hierarchy because they are valued using valuation models with significant unobservable inputs. The following table provides a reconciliation of liabilities measured at fair value using significant unobservable inputs (Level 3) for the six months ended June 30, 2014 (in thousands):



	Common Stock Warrant Liabilities
Balance at December 31, 2013	$	—
Issuance	10,368
Changes in fair value	805
Balance at June 30, 2014	$	11,173

Common stock warrant liabilities are measured at fair value using the Black-Scholes option pricing valuation model. The assumptions used in the Black-Scholes option pricing valuation model for the common stock warrant liabilities were: (a) a risk-free interest rate based on the rates for U.S. Treasury zero-coupon bonds with maturities similar to those of the remaining contractual term of the warrants; (b) an assumed dividend yield of zero based on the Company’s expectation that it will not pay dividends in the foreseeable future; (c) an expected term based on the remaining contractual term of the warrants; and (d) an expected volatility based upon the Company's historical volatility over the remaining contractual term of the warrants. The significant unobservable input used in measuring the fair value of the common stock warrant liabilities associated with the Deerfield Facility Agreement is the expected volatility. Significant increases in volatility would result in a higher fair value measurement. The increase in the fair value of the common stock warrant liabilities as of June 30, 2014 was primarily driven by the increase in the Company's stock price at June 30, 2014 as compared against the the Company's stock price on March 17, 2014, the date the common stock warrants were issued.

Warrants for Common Stock

Common stock warrants that contain compliance covenants and cash payment obligations are classified as common stock warrant liabilities on the consolidated balance sheet. The Company records the warrant liability at fair value and adjusts the carrying value of these common stock warrants to their estimated fair value at each reporting date with the increases or decreases in the fair value of such warrants at each reporting date recorded as other income (expense) in the consolidated statement of operations.

Recent Accounting Pronouncements

In March 2013, the Financial Accounting Standards Board (“FASB”) issued guidance on a parent company’s accounting for the cumulative translation adjustment upon derecognition of a subsidiary or group of assets within a foreign entity. This new guidance requires that the parent release any related cumulative translation adjustment into net income only if the sale or transfer results in the complete or substantially complete liquidation of the foreign entity in which the subsidiary or group of assets had resided. The amendments became effective for the Company beginning January 1, 2014. The Company adopted this guidance and the adoption did not have any impact on the Company's financial statements.

In April 2014, the FASB issued new guidance related to reporting discontinued operations. This new standard raises the threshold for a disposal to qualify as a discontinued operation and requires new disclosures of both discontinued operations and certain other disposals that do not meet the definition of a discontinued operation. The new standard is effective for fiscal years beginning on or after December 15, 2014. The Company is evaluating the impact, if any, of adopting this new accounting standard on its financial statements.

In May 2014, the FASB issued new accounting guidance related to revenue recognition. This new standard will replace all current U.S. GAAP guidance on this topic and eliminate all industry-specific guidance. The new revenue recognition standard provides a unified model to determine when and how revenue is recognized. The core principle is that a company should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration for which the entity expects to be entitled in exchange for those goods or services. This guidance will be effective for the Company. beginning January 1, 2017 and can be applied either retrospectively to each period presented or as a cumulative-effect adjustment as of the date of adoption. The Company is evaluating the impact of adopting this new accounting standard on its financial statements.