Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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Excess of issue price over par or stated value of the entity's capital stock and amounts received from other transactions involving the entity's stock or stockholders. Includes adjustments to additional paid in capital. Some examples of such adjustments include recording the issuance of debt with a beneficial conversion feature and certain tax consequences of equity instruments awarded to employees. Use this element for the aggregate amount of additional paid-in capital associated with common and preferred stock. For additional paid-in capital associated with only common stock, use the element additional paid in capital, common stock. For additional paid-in capital associated with only preferred stock, use the element additional paid in capital, preferred stock.

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Aggregate par or stated value of issued nonredeemable common stock (or common stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable common shares, par value and other disclosure concepts are in another section within stockholders' equity.

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Amount of liabilities classified as other, due after one year or the normal operating cycle, if longer.

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The cumulative amount of the reporting entity's undistributed earnings or deficit.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

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Carrying amount, attributable to parent, of an entity's issued and outstanding stock which is not included within permanent 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. 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. Includes stock with a put option held by an ESOP and stock redeemable by a holder only in the event of a change in control of the issuer.

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Subsequent Events - Pro Forma (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Subsequent Event [Line Items]
Other liabilities	$ 23,945	$ 22,073
Redeemable convertible preferred stock, $0.00001 par value, 928,676 shares authorized; 308,373 shares issued and outstanding as of March 31, 2019 and December 31, 2018, respectively; no shares authorized, issued and outstanding, pro forma	1,465,399	1,465,399	$ 1,465,399	$ 1,465,399
Common stock	1	1
Additional paid-in capital	253,016	252,212
Accumulated other comprehensive loss	(231)	(1,421)
Accumulated deficit	(886,775)	(845,355)
Total stockholders’ equity (deficit)	(633,989)	$ (594,563)	$ (594,963)	$ (546,464)
Pro Forma Adjustments
Subsequent Event [Line Items]
Other liabilities	(5,005)
Redeemable convertible preferred stock, $0.00001 par value, 928,676 shares authorized; 308,373 shares issued and outstanding as of March 31, 2019 and December 31, 2018, respectively; no shares authorized, issued and outstanding, pro forma	(1,465,399)
Common stock	(1)
Additional paid-in capital	3,706,496
Accumulated other comprehensive loss	0
Accumulated deficit	(974,851)
Total stockholders’ equity (deficit)	2,731,649
Pro Forma
Subsequent Event [Line Items]
Other liabilities	18,940
Redeemable convertible preferred stock, $0.00001 par value, 928,676 shares authorized; 308,373 shares issued and outstanding as of March 31, 2019 and December 31, 2018, respectively; no shares authorized, issued and outstanding, pro forma	0
Common stock	0
Additional paid-in capital	3,959,512
Accumulated other comprehensive loss	(231)
Accumulated deficit	(1,861,626)
Total stockholders’ equity (deficit)	2,097,660
Class A common stock
Subsequent Event [Line Items]
Common stock	0
Class A common stock \| Pro Forma Adjustments
Subsequent Event [Line Items]
Common stock	5
Class A common stock \| Pro Forma
Subsequent Event [Line Items]
Common stock	5
Class B common stock
Subsequent Event [Line Items]
Common stock	0
Class B common stock \| Pro Forma Adjustments
Subsequent Event [Line Items]
Common stock	5
Class B common stock \| Pro Forma
Subsequent Event [Line Items]
Common stock	$ 5