Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Numerator:
Net income (loss) - basic	$ (20,829)	$ 47,663	$ (120,434)	$ 85
Change in fair value of financial instruments		(6,700)
Net income (loss) - diluted	$ (20,829)	$ 40,963	$ (120,434)	$ 85
Denominator for basic and diluted weighted average shares of common stock outstanding:
Weighted average common shares outstanding for basic	15,440	14,587	15,164	14,570
Dilutive potential common stock outstanding:
Stock options and Employee Stock Purchase Plan (ESPP)		28
Convertible senior notes		22,000
Weighted average common shares outstanding for diluted	15,440	36,615	15,164	14,570
Basic net income (loss) per share	$ (1.35)	$ 3.27	$ (7.94)	$ 0.01
Diluted net income (loss) per share	$ (1.35)	$ 1.12	$ (7.94)	$ 0.01

Denominator.

No definition available.

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The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of convertible debt securities using the if-converted method.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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Amount of addition (reduction) to the amount at which a liability could be incurred (settled) in a current transaction between willing parties.

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