CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 31, 2018	Dec. 31, 2017
Common stock, par or stated value per share (in usd per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	100,000,000	83,000,000
Common stock, shares issued (in shares)	20,226,000	3,439,000
Common stock, shares outstanding (in shares)	20,226,000	3,439,000
Series G’ Stock
Redeemable convertible preferred stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Redeemable convertible preferred stock, shares authorized (in shares)	0	5,339,000
Redeemable convertible preferred stock, shares issued (in shares)	0	1,295,000
Redeemable convertible preferred stock, shares outstanding (in shares)	0	1,295,000
Series G Stock
Redeemable convertible preferred stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Redeemable convertible preferred stock, shares authorized (in shares)	0	1,385,000
Redeemable convertible preferred stock, shares issued (in shares)	0	346,000
Redeemable convertible preferred stock, shares outstanding (in shares)	0	346,000
Series F-R Stock
Redeemable convertible preferred stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Redeemable convertible preferred stock, shares authorized (in shares)	0	5,000,000
Redeemable convertible preferred stock, shares issued (in shares)	0	1,199,000
Redeemable convertible preferred stock, shares outstanding (in shares)	0	1,199,000
Series E-R Stock
Redeemable convertible preferred stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Redeemable convertible preferred stock, shares authorized (in shares)	0	7,400,000
Redeemable convertible preferred stock, shares issued (in shares)	0	795,000
Redeemable convertible preferred stock, shares outstanding (in shares)	0	795,000
Series D-R Stock
Redeemable convertible preferred stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Redeemable convertible preferred stock, shares authorized (in shares)	0	5,787,000
Redeemable convertible preferred stock, shares issued (in shares)	0	1,396,000
Redeemable convertible preferred stock, shares outstanding (in shares)	0	1,396,000
Series C-R Stock
Redeemable convertible preferred stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Redeemable convertible preferred stock, shares authorized (in shares)	0	6,032,000
Redeemable convertible preferred stock, shares issued (in shares)	0	1,508,000
Redeemable convertible preferred stock, shares outstanding (in shares)	0	1,508,000
Series B-R Stock
Redeemable convertible preferred stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Redeemable convertible preferred stock, shares authorized (in shares)	0	9,596,000
Redeemable convertible preferred stock, shares issued (in shares)	0	2,247,000
Redeemable convertible preferred stock, shares outstanding (in shares)	0	2,247,000
Series A-R Stock
Redeemable convertible preferred stock, par value (in usd per share)	$ 0.0001	$ 0.0001
Redeemable convertible preferred stock, shares authorized (in shares)	0	7,528,000
Redeemable convertible preferred stock, shares issued (in shares)	0	1,857,000
Redeemable convertible preferred stock, shares outstanding (in shares)	0	1,857,000

Face amount or stated value per share of common stock.

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

+ 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

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Per share amount of par value or stated value of stock classified as temporary equity. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable.

+ 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 (27)
-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 480
-SubTopic 10
-Section S99
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=65877616&loc=d3e177068-122764

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The maximum number of securities classified as temporary equity that are permitted to be issued by an entity's charter and bylaws. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

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The number of securities classified as temporary equity that have been sold (or granted) to the entity's shareholders. Securities issued include securities outstanding and securities held in treasury. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. If convertible, the issuer does not control the actions or events necessary to issue the maximum number of shares that could be required to be delivered under the conversion option if the holder exercises the option to convert the stock to another class of equity. If the security is a warrant or a rights issue, the warrant or rights issue is considered to be temporary equity if the issuer cannot demonstrate that it would be able to deliver upon the exercise of the option by the holder in all cases. Includes stock with put option held by ESOP and stock redeemable by holder only in the event of a change in control of the issuer.

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