Stockholders' Equity	12 Months Ended
Dec. 31, 2017
Stockholders' Equity
Stockholders' Equity	8. Stockholders' Equity On September 22, 2017 the Company completed an underwritten public offering of 9,411,765 ordinary shares at a public offering price of $8.50 per share, resulting in gross proceeds of $80.0 million and net proceeds to the Company of $73.3 million, after deducting underwriting discounts and commissions and offering expenses. On December 19, 2016, the Company completed a rights offering and a related underwritten offering for the sale of an aggregate of 588,127 common shares resulting in aggregate gross proceeds of $24.8 million and net proceeds of $20.6 million, after deducting underwriting fees and offering expenses. On September 23, 2015 the Company completed its initial public offering on the Nasdaq Global Market issuing 9,000,000 ADSs at a price to the public of $10.25 per ADS, representing 900,000 of its common shares. Each ADS represents one tenth of a common share. On September 30, 2015 the underwriters of its initial public offering exercised in full their over-allotment option to purchase an additional 1,350,000 ADSs, representing 135,000 common shares, at the initial public offering price of $10.25 per ADS, less underwriting discounts. Including the over-allotment ADSs, the Company sold an aggregate of 10,350,000 ADSs representing 1,035,000 common shares, in its initial public offering, which resulted in gross proceeds of $106.1 million and net proceeds to the Company of $92.4 million, after deducting underwriting discounts and offering expenses. In connection with the Company's April 2015 financing, it sold 730,162 common shares with contractual preference rights under a shareholders agreement, including the sale of 511,188 common shares at a price per share of €82.35 ($87.71) for €42.1 million ($44.8 million) in cash consideration and the sale of 218,974 common shares in exchange for certain contributions in-kind consisting of the conversion of outstanding convertible loans and silent partnership interests. The Company also agreed to sell a second tranche of common shares with contractual preference rights under the shareholders agreement to the investors in its April 2015 financing at their option for an aggregate purchase price of $70.0 million if the Company did not complete a public offering in the United States within specified parameters or by a specified date. As a result of the preferred dividend rights, which were not legally separable, the Company was deemed to have issued common shares accompanied by preferred dividends that may be settled for cash or shares. Accordingly, the proceeds from the April 2015 financing, including the consideration from conversion of the convertible loan agreements and silent partnership interests, were recorded as mezzanine equity. A mezzanine equity classification arises as a result of the dividend provision in the Shareholders Agreement 2015, which the Company's shareholders have covenanted to vote in favor of the requisite shareholder resolutions to allow it to satisfy the preferred dividend rights. As a result, (i) the Company could not avoid fulfilling the preferred dividend rights if a triggering event occurred that was outside its control, and (ii) could not always presume a settlement in shares. Therefore, when a settlement in shares cannot always be presumed for an event not solely within the control of the issuer, irrespective of probability of the event occurring, a classification outside of stockholders' equity is required. Mezzanine equity was initially measured at fair value and subsequently at the redemption value at each reporting period, representing the proceeds resulting from an exit event (trade sale or initial public offering), and such amount recognized in retained earnings. Upon the closing of its initial public offering and the issuance of the shares for nominal value in satisfaction of the preferred dividend rights, all contractual preference rights under the shareholders agreement terminated. In connection with this April 2015 financing, all existing convertible loan agreements and silent partnership interests were converted to common shares with contractual preference rights under the Shareholders Agreement 2015. On March 31, 2015, the Company, its existing investors and new investors in the April 2015 financing signed the Investment and Subscription Agreement 2015, or ISA 2015. The signing of the ISA 2015 resulted in the following effects with respect to the Company's existing financial instruments: a) the lenders under all existing convertible loan agreements, or CLAs, irrevocably waived their claims for payment of interest accrued on the loan amounts, b) all CLA lenders irrevocably waived and acknowledged the termination of their call option rights granted under the CLAs, and c) all silent partners irrevocably agreed to the forfeiture of their claims for payment of interest accrued on their silent partnership investments. The April 2015 financing and the related conversion of the Company's outstanding convertible loan agreements and silent partnership interests resulted in total consideration of $77.3 million which was recorded in mezzanine equity. Upon the closing of the Company's initial public offering in September 2015, a triggering event occurred as described above, and the holders of the preferred dividend right received 17,149 additional shares against payment of the nominal amount of €1.00 per share, effectively removing the mezzanine equity classification.

8. Stockholders' Equity

On September 22, 2017 the Company completed an underwritten public offering of 9,411,765 ordinary shares at a public offering price of $8.50 per share, resulting in gross proceeds of $80.0 million and net proceeds to the Company of $73.3 million, after deducting underwriting discounts and commissions and offering expenses.

On December 19, 2016, the Company completed a rights offering and a related underwritten offering for the sale of an aggregate of 588,127 common shares resulting in aggregate gross proceeds of $24.8 million and net proceeds of $20.6 million, after deducting underwriting fees and offering expenses.

On September 23, 2015 the Company completed its initial public offering on the Nasdaq Global Market issuing 9,000,000 ADSs at a price to the public of $10.25 per ADS, representing 900,000 of its common shares. Each ADS represents one tenth of a common share. On September 30, 2015 the underwriters of its initial public offering exercised in full their over-allotment option to purchase an additional 1,350,000 ADSs, representing 135,000 common shares, at the initial public offering price of $10.25 per ADS, less underwriting discounts. Including the over-allotment ADSs, the Company sold an aggregate of 10,350,000 ADSs representing 1,035,000 common shares, in its initial public offering, which resulted in gross proceeds of $106.1 million and net proceeds to the Company of $92.4 million, after deducting underwriting discounts and offering expenses.

In connection with the Company's April 2015 financing, it sold 730,162 common shares with contractual preference rights under a shareholders agreement, including the sale of 511,188 common shares at a price per share of €82.35 ($87.71) for €42.1 million ($44.8 million) in cash consideration and the sale of 218,974 common shares in exchange for certain contributions in-kind consisting of the conversion of outstanding convertible loans and silent partnership interests. The Company also agreed to sell a second tranche of common shares with contractual preference rights under the shareholders agreement to the investors in its April 2015 financing at their option for an aggregate purchase price of $70.0 million if the Company did not complete a public offering in the United States within specified parameters or by a specified date. As a result of the preferred dividend rights, which were not legally separable, the Company was deemed to have issued common shares accompanied by preferred dividends that may be settled for cash or shares. Accordingly, the proceeds from the April 2015 financing, including the consideration from conversion of the convertible loan agreements and silent partnership interests, were recorded as mezzanine equity. A mezzanine equity classification arises as a result of the dividend provision in the Shareholders Agreement 2015, which the Company's shareholders have covenanted to vote in favor of the requisite shareholder resolutions to allow it to satisfy the preferred dividend rights. As a result, (i) the Company could not avoid fulfilling the preferred dividend rights if a triggering event occurred that was outside its control, and (ii) could not always presume a settlement in shares. Therefore, when a settlement in shares cannot always be presumed for an event not solely within the control of the issuer, irrespective of probability of the event occurring, a classification outside of stockholders' equity is required. Mezzanine equity was initially measured at fair value and subsequently at the redemption value at each reporting period, representing the proceeds resulting from an exit event (trade sale or initial public offering), and such amount recognized in retained earnings.

Upon the closing of its initial public offering and the issuance of the shares for nominal value in satisfaction of the preferred dividend rights, all contractual preference rights under the shareholders agreement terminated.

In connection with this April 2015 financing, all existing convertible loan agreements and silent partnership interests were converted to common shares with contractual preference rights under the Shareholders Agreement 2015.

On March 31, 2015, the Company, its existing investors and new investors in the April 2015 financing signed the Investment and Subscription Agreement 2015, or ISA 2015.

The signing of the ISA 2015 resulted in the following effects with respect to the Company's existing financial instruments:

a) the lenders under all existing convertible loan agreements, or CLAs, irrevocably waived their claims for payment of interest accrued on the loan amounts,

b) all CLA lenders irrevocably waived and acknowledged the termination of their call option rights granted under the CLAs, and

c) all silent partners irrevocably agreed to the forfeiture of their claims for payment of interest accrued on their silent partnership investments.

The April 2015 financing and the related conversion of the Company's outstanding convertible loan agreements and silent partnership interests resulted in total consideration of $77.3 million which was recorded in mezzanine equity. Upon the closing of the Company's initial public offering in September 2015, a triggering event occurred as described above, and the holders of the preferred dividend right received 17,149 additional shares against payment of the nominal amount of €1.00 per share, effectively removing the mezzanine equity classification.