Stockholders' equity (Details) - shares |
Dec. 31, 2017 |
Dec. 31, 2016 |
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| Stockholders' equity | ||
| Common stock authorized (in shares) | 100,000,000 | 100,000,000 |
| Shares of Common Stock reserved | ||
| Total (in shares) | 8,470,000 | 9,485,000 |
| 2001 Plan | ||
| Shares of Common Stock reserved | ||
| Outstanding stock options (in shares) | 155,000 | 1,090,000 |
| 2011 Plan | ||
| Shares of Common Stock reserved | ||
| Outstanding stock options (in shares) | 1,128,000 | 1,994,000 |
| Outstanding RSUs (in shares) | 3,324,000 | 3,825,000 |
| Number of shares available for grant (in shares) | 3,863,000 | 2,576,000 |
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- Definition Aggregate number of common shares reserved for future issuance. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The maximum number of common shares permitted to be issued by an entity's charter and bylaws. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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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. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Number of options outstanding, including both vested and non-vested options. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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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. No definition available.
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- References No definition available.
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