Stock options outstanding.

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- Definition

The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (g)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(iii)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

+ Details

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- Definition

The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

+ Details

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- Definition

The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

+ Details

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- Definition

Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

+ Details

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- Definition

The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(i)-(ii)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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- Definition

Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)(1)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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Stockholders' Equity and Stock-based Compensation - Stock Options Outstanding by Price Range (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2012
Summary of stock options outstanding
Option Price per Share, minimum (usd per share)	$ 3.1	$ 3.1	$ 34.20	$ 37.05
Option Price per Share, maximum (usd per share)	$ 245.85	$ 245.85	$ 245.85	$ 245.85
Outstanding (in shares)	890,341
Weighted Average Exercise Price of Outstanding Options (usd per share)	$ 36.17
Weighted Average Remaining Contract Life	6 years 4 months 24 days
Vested (in shares)	435,278
Weighted Average Exercise Price of Vested Options (usd per share)	$ 63.25
$3.10 - $57.90
Summary of stock options outstanding
Option Price per Share, minimum (usd per share)	3.10
Option Price per Share, maximum (usd per share)	$ 57.90
Outstanding (in shares)	641,030
Weighted Average Exercise Price of Outstanding Options (usd per share)	$ 15.17
Weighted Average Remaining Contract Life	7 years 1 month 6 days
Vested (in shares)	202,312
Weighted Average Exercise Price of Vested Options (usd per share)	$ 29.89
$61.05 - $71.85
Summary of stock options outstanding
Option Price per Share, minimum (usd per share)	61.05
Option Price per Share, maximum (usd per share)	$ 71.85
Outstanding (in shares)	76,963
Weighted Average Exercise Price of Outstanding Options (usd per share)	$ 62.14
Weighted Average Remaining Contract Life	5 years 9 months 18 days
Vested (in shares)	60,618
Weighted Average Exercise Price of Vested Options (usd per share)	$ 62.43
$81.60 - $99.60
Summary of stock options outstanding
Option Price per Share, minimum (usd per share)	81.60
Option Price per Share, maximum (usd per share)	$ 99.60
Outstanding (in shares)	115,742
Weighted Average Exercise Price of Outstanding Options (usd per share)	$ 88.79
Weighted Average Remaining Contract Life	4 years 4 months 24 days
Vested (in shares)	115,742
Weighted Average Exercise Price of Vested Options (usd per share)	$ 88.79
$106.05 - $245.85
Summary of stock options outstanding
Option Price per Share, minimum (usd per share)	106.05
Option Price per Share, maximum (usd per share)	$ 245.85
Outstanding (in shares)	56,606
Weighted Average Exercise Price of Outstanding Options (usd per share)	$ 131.16
Weighted Average Remaining Contract Life	2 years 8 months 12 days
Vested (in shares)	56,606
Weighted Average Exercise Price of Vested Options (usd per share)	$ 131.16