Allocated share based compensation expense liability classified share-based awards.

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Percentage of voting stock.

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Share based compensation arrangement by share based payment award equity instruments other than options granted in period fair value.

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- Definition

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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- Definition

The weighted average fair value at grant date for nonvested equity-based awards issued 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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- Definition

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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- Definition

Number of additional shares authorized for issuance under an established share-based compensation plan.

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No definition available.

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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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- Definition

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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- Definition

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

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- Definition

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

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No definition available.

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- Definition

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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- Definition

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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- Definition

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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- Definition

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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- Definition

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

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No definition available.

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Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Mar. 31, 2018	Jul. 31, 2017	Jan. 31, 2017	Jan. 31, 2016
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	18,297,465	18,297,465
Percentage increase in number of common stock outstanding		5.00%
Term of stock options granted		10 years
Vesting period		4 years
Aggregate intrinsic value of stock options exercised		$ 11,600	$ 39,300	$ 1,000
Total estimated grant date fair value of stock options vested		$ 30,600	$ 23,000	$ 20,800
Weighted-average grant date fair value of stock options granted		$ 21.01	$ 24.08	$ 17.15
Stock-based compensation expense		$ 46,159	$ 43,284	$ 30,362
Unamortized share based compensation expected to be recognized over the remaining vesting period	$ 60,500	$ 60,500
Unamortized share based compensation expected recognition period		2 years 7 months 6 days
Allocated share based compensation liability classified		$ 9,201
Stock-based compensation		$ 55,360	43,284	30,362
Employee stock purchase plan
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	1,818,314	1,818,314
Percentage increase in number of common stock outstanding		2.00%
Common stock reserved, shares	1,505,810	1,505,810
Exercise price of stock options granted as a minimum percentage of fair value of common stock		85.00%
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%
Employee Stock Option
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense		$ 29,700	25,500	21,200
Performance Stock Options (PSOs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Aggregate intrinsic value of stock options exercised		$ 200	400	$ 0
Weighted-average grant date fair value of stock options granted				$ 14.25
Stock-based compensation expense			$ 2,300	$ 500	$ 500
No of shares granted		0	0
Restricted Stock Units (RSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		3 years
Stock-based compensation expense		$ 11,300	$ 8,100	5,300
Unamortized share based compensation expected to be recognized over the remaining vesting period	$ 21,600	$ 21,600
Unamortized share based compensation expected recognition period		2 years
Grant date of fair value		$ 8,000	$ 6,000	$ 1,700
Weighted-average grant date of fair value		$ 37.6	$ 27.15	$ 28.01
Performance Stock Units (PSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation expense		$ 2,700	$ 2,400	$ 2,500
Unamortized share based compensation expected to be recognized over the remaining vesting period	$ 500	$ 500
Unamortized share based compensation expected recognition period		8 months 12 days
Grant date of fair value		$ 5,700	$ 2,100	$ 700
Weighted-average grant date of fair value		$ 32.66	$ 25.54	$ 33.49
Dividend yield		0.00%
Performance Stock Units (PSUs) \| Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares available for issuance						102,600		143,750	102,906
Nonemployee Stock Options
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period		4 years
Share based compensation, options granted		37,000	50,000	52,000
Share based compensation, options weighted average exercise price		$ 45.16	$ 38.14	$ 24.85
Stock-based compensation		$ 12,100	$ 3,900	$ 100
Lonza Award
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Allocated share based compensation liability classified		$ 9,200
2013 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved, shares	5,203,731	5,203,731
2013 Equity Incentive Plan \| Performance Stock Units (PSUs)
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted-average grant date of fair value		$ 32.66
2017 Equity Incentive Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock reserved, shares	1,246,421	1,246,421
Shares available for issuance							1,500,000
Number of additional shares authorized for issuance	1,000,000