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Consecutive trading period required to earn performance stock unit .

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Minimum average market closing price to earn performance stock unit.

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Percentage of voting stock.

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Share based compensation arrangement by share based payment award increase in shares available for issuance percentage of total common stock outstanding.

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Stock option grants exercise price minimum percentage on fair market value.

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Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Aggregate number of common shares reserved for future issuance.

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Unrecognized cost of unvested share-based compensation awards.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Description of award terms as to how many shares or portion of an award are no longer contingent on satisfaction of either a service condition, market condition or a performance condition, thereby giving the employee the legal right to convert the award to shares, to sell the shares, and be entitled to the cash proceeds of such sale. For example, vesting may be expressed as being 25 percent of the shares under option on each anniversary of the grant date.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested).

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Net number of share options (or share units) granted during the period.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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No definition available.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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Purchase price of common stock expressed as a percentage of its fair value.

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Stock-Based Compensation - Additional Information (Detail) - USD ($)	3 Months Ended	12 Months Ended			14 Months Ended
	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2013	Jun. 30, 2015	Jan. 31, 2015
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved, shares	1,422,745	1,422,745
Percentage increase in number of common stock outstanding		5.00%
Number of common stock shares reserved for issuance under the 2013 Employee Stock Purchase Plan	9,387,452	9,387,452
Term of stock options granted		10 years
Vesting period		4 years
Aggregate intrinsic value of stock options exercised		$ 35,900,000	$ 12,500,000		$ 6,300,000
Total estimated grant date fair value of stock options vested		12,000,000	$ 9,000,000	$ 3,800,000
Unamortized share based compensation expected to be recognized over the remaining vesting period	$ 42,400,000	$ 42,400,000
Unamortized share based compensation expected recognition period		2 years 9 months 18 days
Weighted-average per share fair value of employee stock options granted		$ 22.84	$ 15.73	$ 12.46
Stock-based compensation expense		$ 22,858,000	$ 9,333,000	$ 4,974,000
Share based compensation, options weighted average exercise price		$ 38.33
Employee Stock Purchase Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved, shares	1,759,270	1,759,270
Percentage increase in number of common stock outstanding		2.00%
Number of common stock shares reserved for issuance under the 2013 Employee Stock Purchase Plan	1,818,314	1,818,314
Exercise price of stock options granted as a minimum percentage of fair value of common stock		85.00%
Dividend yield		0.00%	0.00%	0.00%
Incentive Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise price of stock options granted as a minimum percentage of fair value of common stock		100.00%
Nonstatutory Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise price of stock options granted as a minimum percentage of fair value of common stock		85.00%
10% or more
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Exercise price of stock options granted as a minimum percentage of fair value of common stock		110.00%
Percentage of voting stock		10.00%
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		3 years
Unamortized share based compensation expected to be recognized over the remaining vesting period	$ 3,300,000	$ 3,300,000
Unamortized share based compensation expected recognition period		2 years
RSUs Vested during the year		0
Stock-based compensation expense		$ 1,500,000
Performance-based RSUs awarded based on achievement of development goals		187,200
Performance Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of common stock shares reserved for issuance under the 2013 Employee Stock Purchase Plan						165,000	165,000
Vesting period		4 years
Unamortized share based compensation expected to be recognized over the remaining vesting period	$ 3,300,000	$ 3,300,000
Unamortized share based compensation expected recognition period		1 year 4 months 24 days
RSUs Vested during the year		0
Stock-based compensation expense		$ 2,300,000
Number of common stock earned per share		1.00%
Vesting rights		At any time during the four years following the date of the grant, a portion of the M-PSUs will vest one year after the date the average closing price of our Common Stock on the NASDAQ Global Select Market is above $50.00 per share for 45 consecutive trading days, and the remaining portion of the grant will vest one year after the date the average closing price of our Common Stock is above $60.00 per share for 45 consecutive trading days
Consecutive trading period required to earn PSU		45 days
Performance-based RSUs awarded based on achievement of development goals	40,496	165,000
Dividend yield		0.00%
Performance Shares \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Performance-based RSUs awarded based on achievement of development goals, available for grant						69,625
Performance Shares \| $50 Vesting Hurdle
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Minimum average market closing price to earn M-PSU		$ 50.00
Performance Shares \| $60 Vesting Hurdle
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Minimum average market closing price to earn M-PSU		$ 60.00
Nonemployee Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		4 years
Share based compensation, options granted		66,041	33,888	32,943
Share based compensation, options weighted average exercise price		$ 40.85	$ 25.41	$ 19.88
Stock-based compensation		$ 2,790,000	$ 769,000	$ 775,000