XML 83 R63.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Compensation and Other Benefit Plans - Additional Information (Details) - USD ($) | 1 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Dec. 31, 2017 | May 31, 2017 | Feb. 28, 2017 | May 31, 2016 | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Apr. 30, 2017
Deferred savings plan [Abstract] |  |  |  |  |  |  |  |
Maximum annual contribution per employee (in hundredths) |  |  |  |  | 50.00% |  |  |
Maximum annual contribution per employee |  |  |  |  | $ 18,000 | $ 18,000 | $ 18,000 |
Maximum annual contribution per employee over 50 years old |  |  |  |  | $ 24,000 | $ 24,000 | $ 24,000 |
Age requirement for participant to be eligible for a catch-up contribution, minimum |  |  |  |  | 50 years | 50 years | 50 years |
Employer matching contribution percentage, maximum (in hundredths) |  |  |  |  | 50.00% |  |  |
Deferred savings plan expense |  |  |  |  | $ 0 | $ 500,000 | $ 800,000 |
Deferred savings plan expense paid in common shares (in hundredths) |  |  |  |  |  | 100.00% | 100.00% |
Number of shares of common stock to be issued upon exercise of options and RSUs outstanding (in shares) | 1,641,492 |  |  |  | 1,641,492 |  |  |
Additional disclosures [Abstract] |  |  |  |  |  |  |  |
Stock-based compensation expense |  |  |  |  | $ 7,301,000 | $ 7,645,000 | $ 9,727,000 |
Non Executive Employee [Member] | Minimum [Member] |  |  |  |  |  |  |  |
Deferred savings plan [Abstract] |  |  |  |  |  |  |  |
Vesting period |  |  |  |  | 3 years |  |  |
Non Executive Employee [Member] | Maximum [Member] |  |  |  |  |  |  |  |
Deferred savings plan [Abstract] |  |  |  |  |  |  |  |
Vesting period |  |  |  |  | 4 years |  |  |
Directors [Member] |  |  |  |  |  |  |  |
Deferred savings plan [Abstract] |  |  |  |  |  |  |  |
Vesting period |  |  |  |  | 1 year |  |  |
Executives [Member] |  |  |  |  |  |  |  |
Additional disclosures [Abstract] |  |  |  |  |  |  |  |
Additional options granted | 130,000 |  |  |  |  |  |  |
Stock Options [Member] |  |  |  |  |  |  |  |
Additional disclosures [Abstract] |  |  |  |  |  |  |  |
Minimum age required for employees to qualify for immediate vesting of RSUs |  |  |  |  | 55 years |  |  |
Threshold years required for retirement age |  |  |  |  | 70 years |  |  |
Options exercised, aggregate intrinsic value |  |  |  |  | $ 2,400,000 |  | $ 400,000 |
Stock options exercised |  |  |  |  | 110,400 | 0 |  |
Weighted-average grant-date fair value |  |  |  |  | $ 10.26 | $ 4.90 | $ 51.92 |
Options outstanding, aggregate intrinsic value | $ 34,300,000 |  |  |  | $ 34,300,000 |  |  |
Options outstanding, weighted average remaining contractual term |  |  |  |  | 7 years 10 months 28 days |  |  |
Options exercisable, aggregate intrinsic value | 18,500,000 |  |  |  | $ 18,500,000 |  |  |
Options exercisable, weighted average remaining contractual term |  |  |  |  | 7 years 7 months 24 days |  |  |
Unrecognized compensation expense related to stock options | $ 8,600,000 |  |  |  | $ 8,600,000 |  |  |
Weighted average period of unrecognized compensation expense expected to be recognized |  |  |  |  | 2 years 2 months 12 days |  |  |
Number of stock options granted to members of board of directors, executives, and non-executive employees |  |  |  |  | 1,387,820 |  |  |
Stock options vested and expected to vest [Abstract] |  |  |  |  |  |  |  |
Options outstanding, number of shares (in shares) | 1,622,065 |  |  |  | 1,622,065 | 568,292 |  |
Options outstanding, weighted-average exercise price (in dollars per share) | $ 24.54 |  |  |  | $ 24.54 | $ 77.70 |  |
Stock option activity [Roll Forward] |  |  |  |  |  |  |  |
Exercisable at end of year (in shares) | 849,279 |  |  |  | 849,279 |  |  |
Performance Shares [Member] |  |  |  |  |  |  |  |
Additional disclosures [Abstract] |  |  |  |  |  |  |  |
Options granted |  |  |  |  | 542,500 |  |  |
Options vested |  |  |  |  | 330,000 |  |  |
Restricted Stock Units (RSUs) [Member] |  |  |  |  |  |  |  |
Additional disclosures [Abstract] |  |  |  |  |  |  |  |
Minimum age required for employees to qualify for immediate vesting of RSUs |  |  |  |  | 55 years |  |  |
Threshold years required for retirement age |  |  |  |  | 70 years |  |  |
Weighted average period of unrecognized compensation expense expected to be recognized |  |  |  |  | 3 months 3 days |  |  |
Unrecognized compensation expense related to employee RSUs | $ 88,000 |  |  |  | $ 88,000 |  |  |
Unvested RSU activity, weighted average grant date fair value [Roll Forward] |  |  |  |  |  |  |  |
Total grant-date fair value of RSUs, vested |  |  |  |  | $ 2,300,000 | $ 5,300,000 | $ 5,500,000 |
Restricted Stock Units (RSUs) [Member] | Non Executive Employee [Member] |  |  |  |  |  |  |  |
Deferred savings plan [Abstract] |  |  |  |  |  |  |  |
Vesting period |  |  |  |  | 3 years |  |  |
Restricted Stock Units (RSUs) [Member] | Directors [Member] |  |  |  |  |  |  |  |
Deferred savings plan [Abstract] |  |  |  |  |  |  |  |
Vesting period |  |  |  |  | 1 year |  |  |
Common Stock [Member] |  |  |  |  |  |  |  |
Additional disclosures [Abstract] |  |  |  |  |  |  |  |
Stock options exercised |  |  |  |  | 110,000 |  |  |
2015 ESPP [Member] |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |
Percentage related to employees to purchase shares at the lower fair market value at offering period |  |  |  |  | 85.00% |  |  |
Common stock reserved for future issuance (in shares) | 15,000 |  |  |  | 15,000 |  |  |
Percentage of compensation of eligible employees to purchase shares of entity common stock at discount through payroll deductions |  |  |  |  | 10.00% |  |  |
Shares purchased (in shares) |  |  |  |  | 5,314 | 7,070 | 6,029 |
2015 ESPP [Member] | Common Stock [Member] |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |
Increase in aggregate number of shares authorized for issuance |  | 250,000 |  |  |  |  |  |
Shares authorized for issuance |  | 265,000 |  |  |  |  |  | 15,000
Increase in shares per person award limits |  | 2,500 |  |  |  |  |  |
2010 Plan [Member] |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |
Increase in aggregate number of shares authorized for issuance |  |  |  | 170,000 |  |  |  |
Shares authorized for issuance |  |  |  | 1,108,560 |  |  |  |
Deferred savings plan [Abstract] |  |  |  |  |  |  |  |
Expiration period |  |  |  |  | ten years from the date of the grant or three to six months from the date of termination of employment (longer in case of death or certain retirements). |  |  |
Vesting period |  |  |  |  | 3 years |  |  |
Additional disclosures [Abstract] |  |  |  |  |  |  |  |
Number of stock options granted to members of board of directors, executives, and non-executive employees |  | 998,000 | 1,018,000 |  |  |  |  |
2010 Plan [Member] | Options and Stock Appreciation Rights [Member] |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |
Increase in shares per person award limits |  | 2,000,000 |  |  |  |  |  |
2010 Plan [Member] | Other Types of Stock Awards [Member] |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |
Increase in shares per person award limits |  | 2,000,000 |  |  |  |  |  |
2010 Plan [Member] | Stock Options [Member] |  |  |  |  |  |  |  |
Additional disclosures [Abstract] |  |  |  |  |  |  |  |
Stock-based compensation expense |  |  |  |  | $ 1,800,000 |  |  |
2010 Plan [Member] | Common Stock [Member] |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |
Increase in aggregate number of shares authorized for issuance |  | 1,470,502 |  |  |  |  |  |
Shares authorized for issuance |  | 2,579,062 |  |  |  |  |  |
2010 Plan [Member] | Common Stock [Member] | Incentive Stock Options [Member] |  |  |  |  |  |  |  |
Share Based Compensation Arrangement By Share Based Payment Award [Line Items] |  |  |  |  |  |  |  |
Increase in aggregate number of shares authorized for issuance |  | 2,004,087 |  |  |  |  |  |
Shares authorized for issuance |  | 2,579,062 |  |  |  |  |  |
Long Term Incentive Plan [Member] |  |  |  |  |  |  |  |
Deferred savings plan [Abstract] |  |  |  |  |  |  |  |
Shares available for grant | 412,314 |  |  |  | 412,314 |  |  |

X
- Definition Aggregate number of common shares reserved for future issuance. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_CommonStockCapitalSharesReservedForFutureIssuance
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_DefinedContributionPensionAndOtherPostretirementPlansDisclosureAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of cost for defined contribution plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942 + Details
Name: | us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Maximum amount the employee may contribute to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeeAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition 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. + 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 (i) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Unrecognized cost of unvested share-based awards, other than options, awarded to employees as compensation. + 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 (i) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Unrecognized cost of unvested options awarded to employees as compensation. + 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 (i) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585 + Details
Name: | us-gaap_ShareBasedCompensation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition 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. + 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 (a)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash. + 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 (d)(2) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition 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. + References No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The highest quantity of shares an employee can purchase under the plan per period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardMaximumNumberOfSharesPerEmployee
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of additional shares authorized for issuance under an established share-based compensation plan. + References No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfAdditionalSharesAuthorized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition 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). + 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 (a)(3) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- 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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalDisclosuresAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan. + 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
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition 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. + 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 (d)(2) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Net number of share options (or share units) granted during the period. + 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)(iv)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Gross number of share options (or share units) granted during the period. + References No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology. + 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 (d)(1) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount by which the current fair value of the underlying stock exceeds the exercise price of options 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 -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Number of options outstanding, including both vested and non-vested options. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 Reference 2: 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
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. + References No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan. + 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) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsVestedAndExpectedToVestAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of shares purchased on the open market during the period for issuance to employees under the plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5047-113901 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesPurchasedForAward
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableIntrinsicValue1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, 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 -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average remaining contractual term for option awards outstanding, 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 + Details
Name: | us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of options vested. + References No definition available. + Details
Name: | us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsVestedNumberOfShares
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Purchase price of common stock expressed as a percentage of its fair value. + References No definition available. + Details
Name: | us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of share options (or share units) exercised during the current period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21463-112644 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iv)(2) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition The age requirement for participants to be eligible for a catch-up contribution amount to a defined contribution plan. + References No definition available. + Details
Name: | xoma_DefinedContributionPlanAgeRequiredForCatchUpContributionMinimum
Namespace Prefix: | xoma_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition The percentage of defined contribution plan expense paid through the issuance of common shares. + References No definition available. + Details
Name: | xoma_DefinedContributionPlanCostRecognizedAndPaidThroughIssuanceOfCommonSharesPercentage
Namespace Prefix: | xoma_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum percentage of employees' salary deferred for which the employer contributes a matching contribution to a defined contribution plan. + References No definition available. + Details
Name: | xoma_DefinedContributionPlanEmployerMatchingContributionPercentOfEmployerSalaryDeferredMaximum
Namespace Prefix: | xoma_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum amount per employee over 50 years old, by the terms of the plan, that the employer may contribute to a defined contribution plan. + References No definition available. + Details
Name: | xoma_DefinedContributionPlanMaximumAnnualContributionPerEmployeeOver50YearsOldAmount
Namespace Prefix: | xoma_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Refers the percentage of compensation deduction in eligible employees salary to purchase entity common stock. + References No definition available. + Details
Name: | xoma_PercentageOfCompensationOfEligibleEmployeesToPurchaseSharesOfEntityCommonStockAtDiscountThroughPayrollDeductions
Namespace Prefix: | xoma_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Description of the period in which the equity-based award expires. + References No definition available. + Details
Name: | xoma_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationPeriodDescription
Namespace Prefix: | xoma_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Minimum age required for employees to qualify for immediate vesting of RSUs. + References No definition available. + Details
Name: | xoma_ShareBasedCompensationArrangementByShareBasedPaymentAwardMinimumAgeRequiredForImmediateVestingOfRsus
Namespace Prefix: | xoma_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Share based compensation arrangement by share based payment award number of shares to be issued upon exercise of options and RSUs outstanding. + References No definition available. + Details
Name: | xoma_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesToBeIssuedUponExerciseOfOptionsAndRSUsOutstanding
Namespace Prefix: | xoma_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Share based compensation arrangement by share based payment award options additional grants in period. + References No definition available. + Details
Name: | xoma_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsAdditionalGrantsInPeriod
Namespace Prefix: | xoma_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Threshold years required for retirement age (defined as employees that are a minimum of 55 years of age and the sum of their age plus years of full-time employment with the Company). + References No definition available. + Details
Name: | xoma_ShareBasedCompensationArrangementByShareBasedPaymentAwardThresholdPeriodForRetirementAge
Namespace Prefix: | xoma_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_TitleOfIndividualAxis=xoma_NonExecutiveEmployeeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TitleOfIndividualAxis=us-gaap_DirectorMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TitleOfIndividualAxis=us-gaap_ExecutiveOfficerMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_PerformanceSharesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_RestrictedStockUnitsRSUMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_CommonStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PlanNameAxis=xoma_TwoThousandFifteenEmployeeStockPurchasePlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PlanNameAxis=xoma_TwoThousandTenLongTermIncentiveAndStockAwardPlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=xoma_OptionsAndStockAppreciationRightsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=xoma_OtherTypesOfStockAwardsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=xoma_IncentiveStockOptionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PlanNameAxis=xoma_LongTermIncentivePlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |