Total Interest Expense Recognized Related to Convertible Notes (Detail) (Senior Notes, USD $) In Thousands, unless otherwise specified	6 Months Ended
Jun. 30, 2014
Senior Notes
Schedule Of Interest Expenses [Line Items]
Contractual interest expense	$ 262
Amortization of debt discount	269
Amortization of debt issuance costs	5
Total interest expense	$ 536

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Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

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Amount of noncash expense included in interest expense to issue debt and obtain financing associated with the related debt instruments. Alternate captions include noncash interest expense.

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Amount of the cost of borrowed funds accounted for as interest expense for debt.

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Represents the portion of interest incurred in the period on debt arrangements that was charged against earnings, excluding amortization of debt discount (premium) and financing costs.

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