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Employee Benefit Plans and Stock-based Compensation - Additional Information (Detail) - USD ($) |  | 1 Months Ended | 2 Months Ended | 3 Months Ended | 6 Months Ended |
--- | --- | --- | --- | --- | --- | ---
Jan. 01, 2017 | Mar. 31, 2017 | Aug. 31, 2016 | Apr. 30, 2017 | Jun. 30, 2017 | Jul. 01, 2016 | Jun. 30, 2017 | Jul. 01, 2016 | Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Increased Number of Common Shares Reserved for Issuance |  |  |  |  |  |  | 7,400,000 |  |
Intrinsic value of options exercised |  |  |  |  | $ 24,000 |  | $ 200,000 |  |
Defined Benefit Plan, Benefit Obligation |  |  |  |  | 4,779,000 |  | 4,779,000 |  | $ 4,300,000
Defined Benefit Pension Plan Liabilities, Current |  |  |  |  | 45,000 |  | 45,000 |  |
Defined Benefit Pension Plan, Liabilities, Noncurrent |  |  |  |  | 4,734,000 |  | $ 4,734,000 |  |
Discretionary contributions of plan |  |  |  |  |  |  | 25.00% |  |
Percent of employees' gross pay eligible for matching |  |  |  |  |  |  | 4.00% |  |
Maximum contribution amount per participant |  |  |  |  |  |  | $ 1,000 |  |
Contributions in period |  |  |  |  |  |  | 285,000 | $ 241,000 |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized |  |  |  |  | 16,500,000 |  | $ 16,500,000 |  |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition |  |  |  |  |  |  | 1 year 7 months 17 days |  |
Total stock-based compensation |  |  |  |  | $ 4,136,000 | $ 2,768,000 | $ 7,387,000 | $ 5,862,000 |
Stock Options [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Volatility |  |  |  |  | 43.00% | 36.00% | 43.00% | 36.00% |
Risk-free interest rate |  |  |  |  | 1.70% | 1.10% | 1.70% | 1.40% |
Expected dividends |  |  |  |  | 0.00% | 0.00% | 0.00% | 0.00% |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value |  |  |  |  | $ 1.85 | $ 1.07 | $ 1.85 | $ 0.97 |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested in Period, Fair Value |  |  |  |  | $ 400,000 | $ 400,000 | $ 1,100,000 | $ 1,400,000 |
Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options |  |  |  |  | 0 | 0 | $ 0 | 0 |
Performance-based Restricted Stock Units [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  | 898,533 | 582,806 |  |  |  |  |
Market-based awards [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period |  |  |  |  |  |  | 344,500 |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period |  |  |  |  |  |  | 3 years |  |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized |  |  |  |  | 900,000 |  | $ 900,000 |  |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition |  |  |  |  |  |  | 8 months 16 days |  |
Volatility |  | 46.70% |  |  |  |  |  |  |
Risk-free interest rate |  | 1.57% |  |  |  |  |  |  |
Expected dividends |  | 0.00% |  |  |  |  |  |  |
Total stock-based compensation |  |  |  |  | 368,000 |  | $ 415,000 |  |
RSUs and PRSUs [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value |  |  |  |  | $ 800,000 | $ 500,000 | $ 7,400,000 | $ 7,100,000 |
Employee Stock Purchase Plan |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Common Stock, Capital Shares Reserved for Future Issuance |  |  |  |  | 1,693,295 |  | 1,693,295 |  |
Discount Percentage On Purchase Of Stock |  |  |  |  |  |  | 15.00% |  |
Percentage of fair market value of Common Stock to purchase shares |  |  |  |  |  |  | 85.00% |  |
Value Of Stock Purchase Right Percentage Of Put Option |  |  |  |  |  |  | 15.00% |  |
Minimum [Member] | Performance-based Restricted Stock Units [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period |  |  |  | 3 months |  |  |  |  |
Maximum [Member] | Performance-based Restricted Stock Units [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period |  |  |  | 6 months |  |  |  |  |
TVN [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Pension and Other Postretirement Benefit Contributions |  |  |  |  | $ 0 |  |  |  |
Stock Plan 1995 [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Increased Number of Common Shares Reserved for Issuance |  |  |  |  | 7,000,000 |  |  |  |
Stock Plan 1995 [Member] | Employee Stock Purchase Plan |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Increased Number of Common Shares Reserved for Issuance |  |  |  |  | 1,500,000 |  |  |  |
Director Option Plans 2002 [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Increased Number of Common Shares Reserved for Issuance |  |  |  |  | 400,000 |  |  |  |
Accounting Standards Update 2016-09 [Member] |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |
Stock Granted, Value, Share-based Compensation, Forfeited | $ 69,000 |  |  |  |  |  |  |  |

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- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5047-113901 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition This represents the current liability recognized in the balance sheet that is associated with the defined benefit pension plans. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e2410-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.24) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e2417-114920 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=64852052&loc=d3e1703-114919 + Details
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- Definition This represents the noncurrent liability recognized in the balance sheet that is associated with the defined benefit pension plans. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e2410-114920 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 210.5-02.24) -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 715 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=64852052&loc=d3e1703-114919 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e2417-114920 + Details
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- Definition 1) For defined benefit pension plans, the benefit obligation is the projected benefit obligation, which is the actuarial present value as of a date of all benefits attributed by the pension benefit formula to employee service rendered prior to that date. 2) For other postretirement defined benefit plans, the benefit obligation is the accumulated postretirement benefit obligation, which is the actuarial present value of benefits attributed to employee service rendered to a particular date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Projected Benefit Obligation -URI http://asc.fasb.org/extlink&oid=6522206 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Accumulated Postretirement Benefit Obligation -URI http://asc.fasb.org/extlink&oid=6503904 + Details
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- Definition Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan. + References No definition available. + Details
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- Definition Unrecognized cost of unvested share-based compensation awards. + 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=6415400&loc=d3e5070-113901 + Details
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- 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=6415400&loc=d3e5070-113901 + Details
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- Definition Disclosure of the aggregate tax benefit realized from the exercise of stock options and the conversion of similar instruments during the annual 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 (j) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The amount of cash or cash equivalents contributed during the reporting period by the entity to fund its pension plans and its non-pension postretirement benefit plans. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 25 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3536-108585 + Details
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- 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=6415400&loc=d3e5070-113901 + Details
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- Definition 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). + 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)(2)(iii)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- 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=6415400&loc=d3e5070-113901 + Details
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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. + 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 (f)(2)(iii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Weighted average expected volatility rate of share-based compensation awards. + 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 (f)(2)(ii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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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. + 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=6415400&loc=d3e5070-113901 + Details
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