Stock-Based Compensation - Employee Stock Purchase Plan (Details) - Employee Stock - $ / shares shares in Thousands	12 Months Ended
Dec. 31, 2020	Apr. 28, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized (in shares)		500
Discount from market price, offering date	90.00%
Percentage of outstanding stock maximum	5.00%
Shares available for issuance, beginning balance (in shares)	293
Employee shares purchased (shares)	(94)
Shares available for issuance, ending balance (in shares)	199
Weighted- Average Purchase Price (in dollars per share)	$ 2.71
Weighted-Average Discount per Share (in dollars per share)	$ 8.15

Share-based Compensation Arrangement by Share-based Payment Award, Weighted Average Discount

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- Definition

Discount rate from fair value on offering date that participants pay for shares.

+ References

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- 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.

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- Definition

Number of shares authorized for issuance under share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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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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- Definition

Per share weighted-average price paid for shares purchased on open market for issuance under share-based payment arrangement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
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-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5047-113901

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- Definition

Maximum number of shares that may be issued in accordance with the plan as a proportion of outstanding capital stock.

+ References

No definition available.

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- Definition

Number of shares purchased for issuance under share-based payment arrangement.

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