Fair Value Measurements

3 Months Ended

Mar. 31, 2015

Fair Value Disclosures [Abstract]

Fair Value Measurements

Fair Value Measurements

Our assets and liabilities which require fair value measurement consist of cash and cash equivalents, marketable securities, accounts receivable, investments, accounts payable, and accrued liabilities. Cash equivalents, accounts receivable, accounts payable and accrued liabilities are stated at carrying amounts as reported in the condensed consolidated financial statements, which approximates fair value due to their short term nature.

Assets and liabilities recorded at fair value on a recurring basis in the accompanying condensed consolidated balance sheets are categorized based upon the level of judgment associated with the inputs used to measure their fair value. Fair value is defined as the exchange price that would be received for an asset or an exit price that would be paid to transfer a liability in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. The authoritative guidance on fair value measurements establishes a three-tier fair value hierarchy for disclosure of the inputs used to measure fair value instruments as follows:

Level I—Inputs are unadjusted, quoted prices in active markets for identical assets or liabilities at the measurement date;

Level II—Inputs are observable, unadjusted quoted prices in active markets for similar assets or liabilities, unadjusted quoted prices for identical or similar assets or liabilities in markets that are not active, or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the related assets or liabilities; and

Level III—Unobservable inputs that are supported by little or no market data for the related assets or liabilities and typically reflect management’s estimate of assumptions that market participants would use in pricing the asset or liability.

Our financial instruments recorded at fair value on a recurring basis consist of Level I assets that include highly liquid money market funds that are included in cash and cash equivalents and U.S. government notes classified as marketable securities. We did not have any Level II or Level III financial instruments recorded at fair value on a recurring basis as of March 31, 2015 and December 31, 2014 .

We measure and report our cash equivalents and available-for-sale marketable securities at fair value. The following table sets forth the fair value of our financial assets by level within the fair value hierarchy (in thousands):

	March 31, 2015
	Level I		Level II		Level III		Total
Financial Assets
Cash and cash equivalents:
Money market funds	$	104,305	$	—	$	—	$	104,305
Marketable securities:
U.S. government notes	209,153		—		—		209,153
Total financial assets	$	313,458	$	—	$	—	$	313,458

	December 31, 2014
	Level I		Level II		Level III		Total
Financial Assets
Cash and cash equivalents:
Money market funds	$	104,216	$	—	$	—	$	104,216
Marketable securities:
U.S. government notes	209,426		—		—		209,426
Total financial assets	$	313,642	$	—	$	—	$	313,642