The number of warrants or rights exercised during period.

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The purchase price of stock from 1997 Employee Stock Purchase Plan will be the lower of the closing price of common stock on: (i) the first trading day in the enrollment period, as defined in the Purchase Plan, in which the purchase is made, or (ii) the purchase date.

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Maximum percent employees can elect to withhold from their base earnings to purchase common stock.

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The weighted average fair value of per share prices paid for shares purchased on the open market for issuance to employees under the plan.

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Number of warrants exercised during the current period.

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

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Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares.

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Aggregate number of common shares reserved for future issuance.

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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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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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

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The cash inflow from the additional capital contribution to the entity.

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The cash inflow from issuance of rights to purchase common shares at predetermined price (usually issued together with corporate debt).

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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

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

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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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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Number of options or other stock instruments for which the right to exercise has lapsed under the terms of the plan agreements.

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The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of shares issued under share-based payment arrangement.

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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options of the plan that expired.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

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Price of a single share of a number of saleable stocks of a company.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of new stock issued during the period.

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Stockholders' Equity - Additional Information (Details) - USD ($)	1 Months Ended															12 Months Ended
	Oct. 31, 2019	Jun. 30, 2019	Jun. 30, 2018	Apr. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Jan. 31, 2017	Jun. 30, 2016	May 31, 2015	Jun. 30, 2014	May 31, 2014	Jun. 30, 2011	May 31, 2010	May 31, 2009	Dec. 31, 2007	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 1997
Class Of Stock [Line Items]
Proceeds from issuance of common stock	$ 162,200,000		$ 194,400,000	$ 168,700,000	$ 142,600,000		$ 163,700,000									$ 162,151,000	$ 363,128,000	$ 306,279,000
Class of warrant or right, number of securities called by warrants or rights																508,000
Share-based compensation arrangements by share-based payment award, options, exercises in period, weighted average exercise price																$ 11.18	$ 11.97	$ 8.49
Common stock, shares, issued, total																90,304,000	78,174,000
Common stock, capital shares reserved for future issuance																31,474,000
Share-based compensation arrangement by share-based payment award, number of shares available for grant																4,971,000
Share-based compensation arrangement by share-based payment award, expiration period																10 years
Share-based compensation arrangement by share-based payment award, award vesting period																4 years
Share-based compensation arrangement by share-based payment award, options, forfeitures in period																1,021,453
Share-based compensation arrangements by share-based payment award, options, forfeitures in period, weighted average exercise price																$ 20.91
Share-based compensation arrangement by share-based payment award, options, expirations in period																528,773
Share-based compensation arrangements by share-based payment award, options, expirations in period, weighted average exercise price																$ 27.81
Share-based compensation arrangement by share-based payment award, options, exercisable, weighted average remaining contractual term																6 years 3 months 18 days
Share-based compensation arrangement by share-based payment award, options, exercises in period, intrinsic value																$ 25,000.0	$ 31,400
Share-based compensation arrangement by share-based payment award, options, outstanding, intrinsic value																$ 56,300	$ 75,700
Common stock future issuance on exercise of outstanding options granted																16,664,640
Total unrecognized compensation cost related to non-vested, stock-based payment awards																$ 128,700
Total unrecognized compensation cost, expect to recognize over weighted average period																3 years
Employee Stock Purchase Plan
Class Of Stock [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares authorized																			10,000
Share-based compensation arrangement by share-based payment award, number of additional shares authorized		300,000				200,000		100,000	100,000		25,000	25,000		10,000	5,000	775,000
Share-based compensation arrangement by share-based payment award maximum employee earnings with held to purchase common stock percent																10.00%
Share-based compensation arrangement by share-based payment award discount on stock price																85.00%
Share-based compensation arrangement by share-based payment award, shares issued in period																125,727	71,499	77,283
Share-based compensation arrangements by share-based payment award, options, exercises in period, weighted average exercise price																$ 16.77	$ 16.48	$ 12.80
Common stock, shares, issued, total																404,909
Common stock, capital shares reserved for future issuance																370,091
Share-based compensation arrangement by share-based payment award, options, grants in period, weighted average grant date fair value																$ 14.70	17.24	10.61
Share-based compensation arrangement by share-based payment award, per share weighted-average fair value price of shares purchased					$ 4.51											$ 5.94	$ 9.95	$ 4.51
Expected life																6 months
Equity Incentive Plan 2007
Class Of Stock [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares authorized															150,000
Share-based compensation arrangement by share-based payment award, number of additional shares authorized		7,000,000				5,000,000		3,000,000	4,300,000		1,750,000	4,500,000	100,000			25,800,000
Share-based compensation arrangement by share-based payment award, number of shares available for grant																4,971,026
Pre-funded Warrants
Class Of Stock [Line Items]
Class of warrant or right, number of securities called by warrants or rights										600,000
Class of warrant or right, exercise price of warrants or rights										$ 0.01
Class of warrant or right, expiration date										Jun. 30, 2021
Class of warrant or right, exercised during period																132,130		4,426
Proceeds from issuance of warrants																$ 1,321,000		$ 0
Class of warrant or right, outstanding																463,444
Common Stock
Class Of Stock [Line Items]
Number of shares issued	9,900,000		5,100,000	6,900,000	9,700,000		14,100,000									9,857,000	11,963,000	23,822,000
Share price	$ 17.50		$ 39.50	$ 26.00	$ 15.50		$ 12.20											$ 15.50
Payments of stock issuance costs	$ 10,300,000		$ 5,600,000	$ 10,700,000	$ 7,400,000		$ 8,800,000
Issuance of common stock on exercise of warrants (in shares)																132,000		4,000
Common Stock \| Pre-funded Warrants
Class Of Stock [Line Items]
Issuance of common stock on exercise of warrants (in shares)																132,130		4,423