Debt Instrument, Interest Rate, Stated Percentage after Extension Option Election

No definition available.

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Data Type:	num:percentItemType
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Period Type:	instant

- Definition

Debt Instrument, Prepayment Penalty

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Extinguishment of Debt, Including Paid in Kind Interest

+ References

No definition available.

+ Details

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Namespace Prefix:	exel_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- 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

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Balance Type:	na
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- Definition

Gross amount of debt extinguished.

+ References

No definition available.

+ Details

Name:	us-gaap_ExtinguishmentOfDebtAmount
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12317-112629

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 50
-Section 40
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=49170532&loc=d3e12355-112629

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of cash paid for interest. Includes, but is not limited to, payment to settle zero-coupon bond attributable to accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4297-108586

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3536-108585

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Interest paid other than in cash for example by issuing additional debt securities. As a noncash item, it is added to net income when calculating cash provided by or used in operations 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 (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

+ Details

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Balance Type:	debit
Period Type:	duration

- Details

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- Details

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- Details

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- Details

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Debt (Secured Convertible Notes) (Details) - USD ($) $ in Thousands		12 Months Ended
	Jun. 28, 2017	Dec. 29, 2017	Dec. 30, 2016	Jan. 01, 2016	Jun. 27, 2017
Debt Instrument [Line Items]
Interest paid in kind		$ (11,825)	$ 8,008	$ 3,817
Accrued and unpaid interest		20,460	21,044	19,822
Loss on extinguishment of debt		$ 6,239	$ 13,901	$ 0
Convertible notes [Member] \| Secured Convertible Notes due June 2018 [Member]
Debt Instrument [Line Items]
Repayment of principal	$ 123,800
Extinguishment of debt amount	113,900
Interest paid in kind	13,900
Prepayment penalty	5,800
Accrued and unpaid interest	4,200
Loss on extinguishment of debt	$ 6,200
Stated interest after extension option election					15.00%
Coupon interest [Member] \| Convertible notes [Member] \| Secured Convertible Notes due June 2018 [Member]
Debt Instrument [Line Items]
Stated interest after extension option election					7.50%
Payment-in-kind interest [Member] \| Convertible notes [Member] \| Secured Convertible Notes due June 2018 [Member]
Debt Instrument [Line Items]
Stated interest after extension option election					7.50%