Document and Entity Information	6 Months Ended
Document and Entity Information	Jun. 30, 2018
Document and Entity Information [Abstract]
Entity Registrant Name	ProQR Therapeutics N.V.
Entity Central Index Key	0001612940
Document Type	6-K
Document Period End Date	Jun. 30, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	H1

Unaudited Condensed Consolidated Statement of Financial Position - EUR (€)	Jun. 30, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	€ 32,968,000	€ 48,099,000
Prepayments and other receivables	1,312,000	2,064,000
Social securities and other taxes	1,014,000	396,000
Total current assets	35,294,000	50,559,000
Property, plant and equipment	2,208,000	2,505,000
Intangible assets	39,000	39,000
Total assets	37,541,000	53,103,000
Equity
Equity attributable to owners of the Company	22,871,000	39,363,000
Non-controlling interests	(140,000)	(38,000)
Total equity	22,731,000	39,325,000
Current liabilities
Borrowings	2,000,000	1,960,000
Trade payables	219,000	546,000
Social securities and other taxes		1,019,000
Deferred income	2,358,000	347,000
Other current liabilities	4,209,000	4,622,000
Total current liabilities	8,786,000	8,494,000
Borrowings	6,024,000	5,284,000
Total liabilities	14,810,000	13,778,000
Total equity and liabilities	€ 37,541,000	€ 53,103,000

Unaudited Condensed Consolidated Statement of Profit or Loss and OCI - EUR (€)
€ in Thousands

3 Months Ended

6 Months Ended

Jun. 30, 2018

Jun. 30, 2017

Jun. 30, 2018

Jun. 30, 2017

Unaudited Condensed Consolidated Statement of Profit or Loss and OCI

Other income

€ 971

€ 265

€ 1,470

€ 658

Research and development costs

(5,990)

(7,552)

(13,675)

(15,582)

General and administrative costs

(2,649)

(2,892)

(5,321)

(5,196)

Total operating costs

(8,639)

(10,444)

(18,996)

(20,778)

Operating result

(7,668)

(10,179)

(17,526)

(20,120)

Finance income and expense

269

(1,184)

(590)

(1,721)

Result before corporate income taxes

(7,399)

(11,363)

(18,116)

(21,841)

Income taxes

(1)

(2)

Result for the period

(7,400)

(11,363)

(18,117)

(21,843)

Other comprehensive income

(11)

Total comprehensive income (attributable to owners of the Company)

(7,385)

(11,300)

(18,128)

(21,778)

Result attributable to

Owners of the Company

(7,342)

(11,363)

(18,015)

(21,843)

Non-controlling interests

(58)

(102)

Result for the period

€ (7,400)

€ (11,363)

€ (18,117)

€ (21,843)

Share information

Weighted average number of shares outstanding

^[1]

31,926,746

23,991,685

31,924,319

23,733,885

Earnings per share attributable to the equity holders of the Company (expressed in Euro per share)

Basic loss per share

^[1]

€ (0.23)

€ (0.47)

€ (0.57)

€ (0.92)

Diluted loss per share

^[1]

€ (0.23)

€ (0.47)

€ (0.57)

€ (0.92)

[1]

For this period presented in these financial statements, the potential exercise of share options is not included in the diluted earnings per share calculation as the Company was loss-making in all periods. Due to the anti-dilutive nature of the outstanding options, basic and diluted earnings per share are equal in this period.

Unaudited Condensed Consolidated Statement of Changes in Equity € in Thousands	Share capital EUR (€)	Share Premium [Member] EUR (€)	Equity Settled Employee Benefit Reserve EUR (€)	Translation Reserve EUR (€)	Accumulated Deficit EUR (€)	Total EUR (€)	Non-controlling interests [Member] EUR (€)	EUR (€) Options shares
Balance at beginning of period at Dec. 31, 2016	€ 934	€ 123,597	€ 4,353	€ (15)	€ (75,733)	€ 53,136		€ 53,136
Balance at beginning of period (in shares) at Dec. 31, 2016 \| shares								23,346,856
Result for the period					(21,843)	(21,843)		€ (21,843)
Other comprehensive income				65		65		65
Recognition of share-based payments			2,200			2,200		2,200
Issue of ordinary shares	30	3,193				3,223		€ 3,223
Issue of ordinary shares (in shares) \| shares								758,012
Shares options exercised	0	1				1		€ 1
Share options exercised (in shares) \| Options								381
Balance at end of period at Jun. 30, 2017	964	126,791	6,553	50	(97,576)	36,782		€ 36,782
Balance at end of period (in shares) at Jun. 30, 2017 \| shares								24,105,249
Balance at beginning of period at Dec. 31, 2017	1,457	148,763	8,377	136	(119,370)	39,363	€ (38)	€ 39,325
Balance at beginning of period (in shares) at Dec. 31, 2017 \| shares								36,425,014
Result for the period					(18,015)	(18,015)	(102)	€ (18,117)
Other comprehensive income				(11)		(11)		(11)
Recognition of share-based payments			1,511			1,511		1,511
Shares options exercised		23				23		23
Balance at end of period at Jun. 30, 2018	€ 1,457	€ 148,786	€ 9,888	€ 125	€ (137,385)	€ 22,871	€ (140)	€ 22,731
Balance at end of period (in shares) at Jun. 30, 2018 \| shares								36,425,014

- Definition

The amount of residual interest in the assets of the entity after deducting all its liabilities.

+ References + Details

- Definition

The total of income less expenses, excluding the components of other comprehensive income. [Refer: Other comprehensive income]

+ References

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+ Details

Unaudited Condensed Consolidated Statement of Cash Flows - EUR (€)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Cash flow from operating activities
Net result	€ (7,400,000)	€ (11,363,000)	€ (18,117,000)	€ (21,843,000)
Adjustments for:
Depreciation	243,000	272,000	483,000	540,000
Share-based compensation	640,000	1,273,000	1,511,000	2,200,000
Financial income and expenses	(269,000)	1,184,000	590,000	1,721,000
Net foreign exchange gain / (loss)	15,000	63,000	(11,000)	65,000
Changes in working capital	1,354,000	(1,275,000)	418,000	(1,368,000)
Cash used in operations	(5,417,000)	(9,846,000)	(15,126,000)	(18,685,000)
Corporate income tax paid	(1,000)		(1,000)	(2,000)
Interest received/(paid)	(6,000)	1,000	(7,000)	59,000
Net cash used in operating activities	(5,424,000)	(9,845,000)	(15,134,000)	(18,628,000)
Cash flow from investing activities
Purchases of property, plant and equipment	(182,000)	(48,000)	(186,000)	(93,000)
Net cash used in investing activities	(182,000)	(48,000)	(186,000)	(93,000)
Cash flow from financing activities
Proceeds from issuance of shares, net of transaction costs		1,072,000		3,223,000
Proceeds from exercise of share options	23,000		23,000	1,000
Proceeds from borrowings		101,000	101,000	101,000
Proceeds from convertible loans	115,000		315,000
Net cash generated by financing activities	138,000	1,173,000	439,000	3,325,000
Net increase/(decrease) in cash and cash equivalents	(5,468,000)	(8,720,000)	(14,881,000)	(15,396,000)
Currency effect cash and cash equivalents	435,000	(1,070,000)	(250,000)	(1,483,000)
Cash and cash equivalents, at beginning of the period	38,001,000	52,111,000	48,099,000	59,200,000
Cash and cash equivalents at the end of the period	€ 32,968,000	€ 42,321,000	€ 32,968,000	€ 42,321,000

General Information

6 Months Ended

Jun. 30, 2018

General Information

General Information

1. General information

ProQR Therapeutics N.V., or “ProQR” or the “Company”, is a development stage company domiciled in the Netherlands that primarily focuses on the development and commercialization of novel therapeutic medicines.

Since September 18, 2014, the Company’s ordinary shares are listed on the NASDAQ Global Market under ticker symbol PRQR.

The Company was incorporated in the Netherlands, on February 21, 2012 and was reorganized from a private company with limited liability to a public company with limited liability on September 23, 2014. The Company has its statutory seat in Leiden, the Netherlands. The address of its headquarters and registered office is Zernikedreef 9, 2333 CK Leiden, the Netherlands.

ProQR Therapeutics N.V. is the ultimate parent company of the following entities:

ProQR Therapeutics Holding B.V. (100%);

ProQR Therapeutics I B.V. (100%);

ProQR Therapeutics II B.V. (100%);

ProQR Therapeutics III B.V. (100%);

ProQR Therapeutics IV B.V. (100%);

ProQR Therapeutics VI B.V. (100%);

ProQR Therapeutics VII B.V. (100%);

ProQR Therapeutics VIII B.V. (100%);

ProQR Therapeutics IX B.V. (100%);

ProQR Therapeutics I Inc. (100%);

Amylon Therapeutics B.V. (majority interest).

ProQR Therapeutics N.V. is also statutory director of Stichting Bewaarneming Aandelen ProQR (“ESOP Foundation”) and has full control over this entity.

As used in these condensed consolidated financial statements, unless the context indicates otherwise, all references to “ProQR” or the “Company” refer to ProQR Therapeutics N.V. including its subsidiaries and the ESOP Foundation.

Significant Accounting Policies	6 Months Ended
Significant Accounting Policies	Jun. 30, 2018
Significant Accounting Policies
Significant Accounting Policies	2. Significant Accounting Policies These condensed consolidated financial statements have been prepared in accordance with International Financial Reporting Standards (“IFRS”), as issued by the International Accounting Standards Board (“IASB”), in particular IAS 34 - Interim Financial Reporting. Certain information and disclosures normally included in financial statements prepared in accordance with IFRS have been condensed or omitted. Accordingly, these condensed consolidated financial statements should be read in conjunction with the Company’s annual financial statements for the year ended December 31, 2017. In the opinion of management, all adjustments, consisting of normal recurring nature, considered necessary for a fair presentation have been included in the condensed consolidated financial statements. The Company’s financial results have varied substantially, and are expected to continue to vary, from period to period. The Company believes that its ordinary activities are not linked to any particular seasonal factors. The Company operates in one reportable segment, which comprises the discovery and development of innovative, RNA based therapeutics.

Adoption of new and revised International Financial Reporting Standards	6 Months Ended
	Jun. 30, 2018
Adoption of new and revised International Financial Reporting Standards
Adoption of new and revised International Financial Reporting Standards	3. Adoption of new and revised International Financial Reporting Standards The accounting policies adopted in the preparation of the condensed consolidated financial statements are consistent with those applied in the preparation of the Company’s annual financial statements for the year ended December 31, 2017. New Standards and Interpretations, which became effective as of January 1, 2018, did not have a material impact on our condensed consolidated financial statements.

Critical Accounting Estimates and Judgments	6 Months Ended
Critical Accounting Estimates and Judgments	Jun. 30, 2018
Critical Accounting Estimates and Judgments
Critical Accounting Estimates and Judgments	4. Critical Accounting Estimates and Judgments In the application of the Company’s accounting policies, management is required to make judgments, estimates and assumptions about the carrying amounts of assets and liabilities that are not readily apparent from other sources. The estimates and associated assumptions are based on historical experience and other factors that are considered to be relevant. Actual results may differ from these estimates. The estimates and underlying assumptions are reviewed on an ongoing basis. Revisions to accounting estimates are recognized in the period in which the estimate is revised if the revision affects only that period or in the period of the revision and future periods if the revision affects both current and future periods. (a) Share-based payments Share options granted to employees and consultants are measured at the fair value of the equity instruments granted. Fair value is determined through the use of the Black-Scholes option-pricing model, which is considered the most appropriate model for this purpose by management. Initially, the Company’s ordinary shares were not publicly traded and consequently the Company needed to estimate the fair value of its share and the expected volatility of that value. Please refer to the Company’s annual financial statements for the year ended December 31, 2017 for the assumptions used in those estimates. The value of the underlying shares was determined on the basis of the prior sale of company stock method. As such, the Company has benchmarked the value per share to external transactions of Company shares and external financing rounds. For options granted from the moment of listing, the Company uses the closing price of the ordinary shares on the previous business day as exercise price of the options granted. The result of the share option valuations and the related compensation expense is dependent on the model and input parameters used. Even though Management considers the fair values reasonable and defensible based on the methodologies applied and the information available, others might derive a different fair value for the Company’s share options. (b) Corporate income taxes The Company recognizes deferred tax assets arising from unused tax losses or tax credits only to the extent that the Company has sufficient taxable temporary differences or there is convincing evidence that sufficient taxable profit will be available against which the unused tax losses or unused tax credits can be utilized. Management’s judgment is that such convincing evidence is currently not sufficiently available and a deferred tax asset is therefore only recognized to the extent that the Company has sufficient taxable temporary differences. (c) Grant income Grant income is not recognized until there is reasonable assurance that the Company will comply with the conditions attached to them. Grants are recognized in profit or loss on a systematic basis over the period the Company recognizes as expenses the related costs for which the grants are expected to compensate. (d) Research and development expenditures Research expenditures are currently not capitalized but are reflected in the income statement because the criteria for capitalization are not met. At each balance sheet date, the Company estimates the level of service performed by the vendors and the associated costs incurred for the services performed. Although we do not expect the estimates to be materially different from amounts actually incurred, the understanding of the status and timing of services performed relative to the actual status and timing of services performed may vary and could result in reporting amounts that are too high or too low in any particular period. The condensed consolidated financial statements do not include all disclosures for critical accounting estimates and judgments that are required in the annual consolidated financial statements and should be read in conjunction with the Company’s annual financial statements for the year ended December 31, 2017.

Cash and Cash Equivalents	6 Months Ended
Cash and Cash Equivalents	Jun. 30, 2018
Cash and Cash Equivalents.
Cash and Cash Equivalents	5. Cash and Cash Equivalents At June 30, 2018, the Company’s cash and equivalents were € 32,968,000 as compared to € 48,099,000 at December 31, 2017. A significant portion of the cash balance is denominated in US dollars. The cash balances are held at banks with investment grade credit ratings. The cash at banks is at full disposal of the Company.

Borrowings

6 Months Ended

Jun. 30, 2018

Borrowings

Borrowings

7. Borrowings



	June 30,	December 31,
	2018	2017
	€ 1,000	€ 1,000
Innovation credit	5,000	4,899
Accrued interest on innovation credit	2,016	1,683
Convertible notes	1,008	662

Total borrowings	8,024	7,244
Current portion	(2,000)	(1,960)
	6,024	5,284

Innovation credit (“Innovatiekrediet”)

On June 1, 2012, ProQR was awarded an Innovation credit by the Dutch government, through its agency RVO of the Ministry of Economic Affairs, for the Company’s cystic fibrosis program. Amounts were drawn under this facility in the course of the years 2013 through 2018. The credit covers 35% of the costs incurred in respect of the program up to an initial maximum of € 5.0 million through March 31, 2018.

The credit is interest-bearing at a rate of 10% per annum. The credit, including accrued interest, is repayable in three instalments on November 30, 2018, November 30, 2019 and November 30, 2020, depending on the technical success of the program.

The assets which are co-financed with the granted innovation credit are subject to a right of pledge for the benefit of RVO.

Convertible loans

Convertible loans were issued to Amylon Therapeutics B.V. in 2017 and are interest-bearing at an average rate of 8% per annum. They are convertible into a variable number of ordinary shares within 36 months at the option of the holder or the Company in case financing criteria are met. Any unconverted loans become payable on demand after 24 months in equal quarterly terms.

Shareholders' equity	6 Months Ended
Shareholders' equity	Jun. 30, 2018
Shareholders' equity
Shareholders' equity	8. Shareholders’ equity The authorized share capital of the Company amounting to € 7,200,000 consists of 90,000,000 ordinary shares and 90,000,000 preference shares with a par value of € 0.04 per share. At June 30, 2018, 36,425,014 ordinary shares were issued and fully paid in cash, of which 4,490,378 were held by the Company as treasury shares (31 December 2017: 4,503,149). On October 2, 2015, the Company filed a shelf registration statement, which permitted: (a) the offering, issuance and sale by the Company of up to a maximum aggregate offering price of $ 200,000,000 of its ordinary shares, warrants and/or units; and (b) as part of the $ 200,000,000, the offering, issuance and sale by us of up to a maximum aggregate offering price of $ 60,000,000 of its ordinary shares that may be issued and sold under a sales agreement in one or more at-the-market offerings. In 2017, the Company has issued 976,477 shares pursuant to its current at-the-market offering program, resulting in proceeds of € 4,138,000, net of € 127,000 of offering expenses. In 2018, no shares were issued pursuant to our ATM facility. On June 28, 2017, the Company agreed to the issuance of 1,200,000 ordinary shares to institutional investors at an issue price of $ 5.00 per share in a registered direct offering with gross proceeds of € 5,278,000. The closing of the offering was effected on July 3, 2017. Transaction costs amounted to € 414,000, resulting in net proceeds of € 4,864,000. In November 2017, the Company consummated an underwritten public offering and concurrent registered direct offering of 6,397,498 ordinary shares at an issue price of $ 3.25 per share. The gross proceeds from both offerings amounted to € 17,671,000 while the transaction costs amounted to € 988,000, resulting in net proceeds of € 16,683,000. Translation reserve The translation reserve comprises all foreign currency differences arising from the translation of the financial statements of foreign operations. Share options The Company operates an equity-settled share-based compensation plan which was introduced in 2013. Options may be granted to employees, members of the Supervisory Board, members of the Management Board and consultants. The quarterly compensation expenses included in operating costs for this plan in 2018 were € 1,511,000 (2017: € 1,273,000), of which € 873,000 (2017: € 627,000) was recorded in general and administrative costs and € 638,000 (2017: € 646,000) was recorded in research and development costs.

Other income

6 Months Ended

Jun. 30, 2018

Other income

Other income

9. Other income



	Three month period ended June 30,

	2018	2017
	€ 1,000	€ 1,000

Grant income	861	154
Rental income from property subleases	110	111
	971	265

On February 9, 2018, the Company entered into a partnership agreement with Foundation Fighting Blindness (FFB), under which FFB has agreed to provide funding of $7.5 million for the pre-clinical and clinical development of QR‑421a for Usher syndrome type 2A targeting mutations in exon 13.

On June 5, 2018, the Company entered into a partnership agreement with EB Research Partnership (EBRP) and EB Medical Research Foundation (EBMRF) under which EBRP and EBMRF have agreed to provide funding of $5.0 million for the clinical development of QR‑313 for Dystrophic Epidermolysis Bullosa targeting mutations in exon 73.

In addition, funding was received in 2018 for our Huntington’s disease program.

Grants are recognized in other income in the same period in which the related R&D costs are recognized.

Research and development costs	6 Months Ended
Research and development costs	Jun. 30, 2018
Research and development costs
Research and development costs	10. Research and development costs Research and development costs amount to € 5,990,000 for the quarter ended June 30, 2018 compared to € 7,552,000 for same period in 2017 and comprised of allocated employee costs including share-based payments, the costs of materials and laboratory consumables, outsourced activities, license and intellectual property costs and other allocated costs.

Income taxes	6 Months Ended
Income taxes	Jun. 30, 2018
Income taxes
Income taxes	12. Income taxes Due to the operating losses incurred since inception the Company has no tax provisions as of the balance sheet date. Furthermore, no significant temporary differences exist between accounting and tax results. Realization of deferred tax assets is dependent on future earnings, if any, the timing and amount of which are uncertain. Accordingly, the Company has not yet recognized any deferred tax asset related to operating losses.

Borrowings (Tables)

6 Months Ended

Jun. 30, 2018

Borrowings

Schedule of borrowings



	June 30,	December 31,
	2018	2017
	€ 1,000	€ 1,000
Innovation credit	5,000	4,899
Accrued interest on innovation credit	2,016	1,683
Convertible notes	1,008	662

Total borrowings	8,024	7,244
Current portion	(2,000)	(1,960)
	6,024	5,284

Other income (Tables)

6 Months Ended

Jun. 30, 2018

Other income

Other income



	Three month period ended June 30,

	2018	2017
	€ 1,000	€ 1,000

Grant income	861	154
Rental income from property subleases	110	111
	971	265

General Information (Details)	6 Months Ended
General Information (Details)	Jun. 30, 2018
ProQR Therapeutics Holding B.V. [Member]
Disclosure of subsidiaries [line items]
Proportion of ownership interest in subsidiary	100.00%
ProQR Therapeutics I B.V. [Member]
Disclosure of subsidiaries [line items]
Proportion of ownership interest in subsidiary	100.00%
ProQR Therapeutics II B.V. [Member]
Disclosure of subsidiaries [line items]
Proportion of ownership interest in subsidiary	100.00%
ProQR Therapeutics III B.V. [Member]
Disclosure of subsidiaries [line items]
Proportion of ownership interest in subsidiary	100.00%
ProQR Therapeutics IV B.V. [Member]
Disclosure of subsidiaries [line items]
Proportion of ownership interest in subsidiary	100.00%
ProQR Therapeutics VI B.V. [Member]
Disclosure of subsidiaries [line items]
Proportion of ownership interest in subsidiary	100.00%
ProQR Therapeutics VII B.V. [Member]
Disclosure of subsidiaries [line items]
Proportion of ownership interest in subsidiary	100.00%
ProQR Therapeutics VIII B.V. [Member]
Disclosure of subsidiaries [line items]
Proportion of ownership interest in subsidiary	100.00%
ProQR Therapeutics IX B.V. [Member]
Disclosure of subsidiaries [line items]
Proportion of ownership interest in subsidiary	100.00%
ProQR Therapeutics I Inc. [Member]
Disclosure of subsidiaries [line items]
Proportion of ownership interest in subsidiary	100.00%

Cash and Cash Equivalents (Details) - EUR (€)	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016
Cash and Cash Equivalents.
Cash and cash equivalents	€ 32,968,000	€ 38,001,000	€ 48,099,000	€ 42,321,000	€ 52,111,000	€ 59,200,000

Borrowings (Details)		12 Months Ended
Borrowings (Details)	Jun. 01, 2012 EUR (€) installment	Dec. 31, 2017 EUR (€)	Jun. 30, 2018 EUR (€)
Disclosure of detailed information about borrowings [line items]
Total borrowings		€ 7,244,000	€ 8,024,000
Current portion		(1,960,000)	(2,000,000)
Non Current portion		5,284,000	6,024,000
Innovation credit
Disclosure of detailed information about borrowings [line items]
Total borrowings		4,899,000	5,000,000
Accrued interest on innovation credit		1,683,000	2,016,000
Percentage of cost covered by the innovative credit	35.00%
Maximum initial borrowing base	€ 5,000,000.00000
Interest rate	10.00%
Number of installments \| installment	3
Convertible notes
Disclosure of detailed information about borrowings [line items]
Total borrowings		€ 662,000	€ 1,008,000
Interest rate		8.00%
Debt instrument convertible term		36 months
Unconvertible debt maturity		P24M

Shareholders' equity - Share capital (Details) - EUR (€)		1 Months Ended	6 Months Ended	12 Months Ended
	Jun. 28, 2017	Nov. 30, 2017	Jun. 30, 2017	Dec. 31, 2017	Jun. 30, 2018	Dec. 31, 2016	Oct. 02, 2015
Shareholders' Equity
Number of shares issued					0
Authorized share capital					€ 7,200,000
Number of shares outstanding			24,105,249	36,425,014	36,425,014	23,346,856
Maximum aggregate offering of ordinary shares							€ 200,000,000
Par value per share					€ 0.04
Treasury shares				4,503,149	4,490,378
Shares issued in the period			€ 3,223,000
Ordinary
Shareholders' Equity
Number of shares authorised					90,000,000
Preferred
Shareholders' Equity
Number of shares authorised					90,000,000
Market offering program
Shareholders' Equity
Number of shares issued				976,477
Transaction cost				€ 127,000
Net proceeds				€ 4,138,000
Institutional investors
Shareholders' Equity
Number of shares issued	1,200,000
Share price	€ 5.00
Gross proceeds	€ 5,278,000
Transaction cost	414,000
Net proceeds	€ 4,864,000
Underwritten public offering and direct offering
Shareholders' Equity
Number of shares issued		6,397,498
Share price		€ 3.25
Gross proceeds		€ 17,671,000
Transaction cost		988,000
Net proceeds		€ 16,683,000
Cantor Fitzgerald & Co \| Ordinary
Shareholders' Equity
Maximum aggregate offering of ordinary shares							€ 60,000,000

Shareholders' equity - Share options (Details) - EUR (€)	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Shareholders' equity
Compensation expenses	€ 1,511,000	€ 1,273,000
Compensation expenses recorded in general and administrative costs	873,000	627,000
Compensation expenses recorded in research and development costs	€ 638,000	€ 646,000

Other income (Details) - EUR (€) € in Thousands	3 Months Ended		6 Months Ended
Other income (Details) - EUR (€) € in Thousands	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Other income
Grant income	€ 861	€ 154
Rental income from property subleases	110	111
Total other income.	€ 971	€ 265	€ 1,470	€ 658

Other income - Narrative (Details) € in Thousands, $ in Millions			3 Months Ended
	Jun. 05, 2018 USD ($)	Feb. 09, 2018 USD ($)	Jun. 30, 2018 EUR (€)	Jun. 30, 2017 EUR (€)
Other Income [Line Items]
Grant income \| €			€ 861	€ 154
EBRP and EBMRF
Other Income [Line Items]
Contribution to support clinical development	$ 5.0
Entering into partnership \| Clinical support agreement \| Foundation Fighting Blindness
Other Income [Line Items]
Contribution to support clinical development		$ 7.5

General and administrative costs	6 Months Ended
General and administrative costs	Jun. 30, 2018
General and administrative costs
General and administrative costs	11. General and administrative costs General and administrative costs amount to € 2,649,000 for the quarter ended June 30, 2018 compared to € 2,892,000 for the quarter ended June 30, 2017.

Events after balance sheet date	6 Months Ended
Events after balance sheet date	Jun. 30, 2018
Events after balance sheet date
Events after balance sheet date	13. Events after balance sheet date No significant events have occurred after balance sheet date.

Significant Accounting Policies (Details)	6 Months Ended
Significant Accounting Policies (Details)	Jun. 30, 2018 segment
Significant Accounting Policies
Number of reportable segment	1

General and administrative expense (Details) - EUR (€) € in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
General and administrative costs
General and administrative expense	€ 2,649	€ 2,892	€ 5,321	€ 5,196

Current liabilities	6 Months Ended
Current liabilities	Jun. 30, 2018
Current liabilities.
Current liabilities	6. Current liabilities At June 30, 2018 and December 31, 2017, the other current liabilities consisted principally of accruals for services provided by vendors not yet billed and other miscellaneous liabilities.