Stockholders' Equity - Common Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended
Oct. 31, 2017	Mar. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Sales commission percentage	3.00%
Number of shares issued in transaction (in shares)		48,634
Shares issued, gross consideration received		$ 1,030
Proceeds from issuance of common shares		1,000
Remaining authorized repurchase amount		19,000
Payments of stock issuance costs		$ 400
Exercise price of warrants (in dollars per share)		$ 10.00
Proceeds from issuance of warrants		$ 24
Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock newly-issued during the period (in shares)		51,034
Stock issued upon exercise of options (in shares)		2,400

Sale Of Stock, Gross Proceeds

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- Definition

Stock Repurchase Program, Sales Commission Percentage

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- Definition

Exercise price per share or per unit of warrants or rights outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(i)(4))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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The cash outflow for cost incurred directly with the issuance of an equity security.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
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The cash inflow associated with the amount received from holders exercising their stock warrants.

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Cash received on stock transaction after deduction of issuance costs.

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The number of shares issued or sold by the subsidiary or equity method investee per stock transaction.

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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.

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- Definition

Number of new stock issued during the period.

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-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
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-Name Accounting Standards Codification
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Gross number of shares (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP). Shares issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans.

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Amount remaining of a stock repurchase plan authorized.

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