Significant Accounting Policies (Tables)

6 Months Ended

Jun. 30, 2013

Summarizes changes in other accumulated other comprehensive income (loss) related to unrealized gains and losses on securities

The following table summarizes changes in accumulated other comprehensive income (loss) for the three and six months ended June 30, 2013 and 2012 (in thousands):

	Three Months Ended June 30,					Six Months Ended June 30,
	2013		2012			2013			2012

Beginning balance accumulated other comprehensive income (loss)	$	17,784	$	(242	)	$	12,480		$	(770	)
Other comprehensive income before reclassifications, net of tax (1)	9,202		1,210			15,669			1,738
Amounts reclassified from accumulated other comprehensive income (2)	—		—			(1,163		)	—
Net current period other comprehensive income	9,202		1,210			14,506			1,738
Ending balance accumulated other comprehensive income	$	26,986	$	968		$	26,986		$	968

(1) Other comprehensive income for the three and six months ended June 30, 2013 includes income tax expense of $6.3 million and $10.0 million, respectively.

(2) Included in gain on investments, net on our condensed consolidated statement of operations.

Stock-based compensation expense

Schedule of weighted-average assumptions used for valuation of ESPP

	Six Months Ended June 30,
	2013		2012
Risk-free interest rate	0.1	%	0.1	%
Dividend yield	0.0	%	0.0	%
Volatility	61.4	%	42.3	%
Expected life	6 months		6 months

Schedule of stock-based compensation expense

The following table summarizes stock-based compensation expense for the three and six months ended June 30, 2013 and 2012 (in thousands), which was allocated as follows:

	Three Months Ended June 30,				Six Months Ended June 30,
	2013		2012		2013		2012

Research and development	$	2,252	$	2,073	$	4,798	$	4,008
General and administrative	384		387		707		719
Total	$	2,636	$	2,460	$	5,505	$	4,727

Employee Stock Options:

Stock-based compensation expense

Schedule of weighted-average assumptions used for valuation of stock options

	Six Months Ended June 30,
	2013		2012
Risk-free interest rate	1.0	%	0.8	%
Dividend yield	0.0	%	0.0	%
Volatility	51.5	%	51.1	%
Expected life	5.1 years		5.1 years

Board of Director Stock Options:

Stock-based compensation expense

Schedule of weighted-average assumptions used for valuation of stock options

	Six Months Ended June 30,
	2013
Risk-free interest rate	2.3	%
Dividend yield	0.0	%
Volatility	52.4	%
Expected life	7.3 years

- Definition

Tabular disclosure of components of comprehensive income (loss) including, but not limited to: (a) foreign currency translation adjustments; (b) gains (losses) on foreign currency transactions that are designated as, and are effective as, economic hedges of a net investment in a foreign entity; (c) gains (losses) on intercompany foreign currency transactions that are of a long-term-investment nature, when the entities to the transaction are consolidated, combined, or accounted for by the equity method in the reporting enterprise's financial statements; (d) change in the market value of a futures contract that qualifies as a hedge of an asset reported at fair value; (e) unrealized holding gains (losses) on available-for-sale securities and that resulting from transfers of debt securities from the held-to-maturity category to the available-for-sale category; (f) a net loss recognized as an additional pension liability not yet recognized as net periodic pension cost; and (g) the net gain (loss) and net prior service cost or credit for pension plans and other postretirement benefit plans.

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- Definition

Tabular disclosure of the allocation of equity-based compensation costs to a given line item on the balance sheet and income statement for the period. This may include the reporting line for the costs and the amount capitalized and expensed.

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