Stockholders’ Equity	12 Months Ended
Dec. 31, 2017
Equity [Abstract]
Stockholders’ Equity	10. Stockholders’ Equity On May 11, 2016, the Company completed an initial public offering (“IPO”) of its common stock, which resulted in the sale of 6,900,000 shares, including all additional shares available to cover over-allotments, at a price of $18.00 per share. The Company received net proceeds before expenses from the IPO of $115.5 million after deducting underwriting discounts and commissions paid by the Company. In preparation for the IPO, the Company’s board of directors and stockholders approved a one-for-1.7 reverse stock split of the Company’s common stock effective April 25, 2016. All share and per share amounts in the consolidated financial statements and notes thereto have been retroactively adjusted, where necessary, to give effect to this reverse stock split. In connection with the closing of the IPO, all of the Company’s outstanding convertible preferred stock automatically converted to common stock at a one-for-0.6465903 ratio as of May 11, 2016, resulting in an additional 23,481,956 shares of common stock of the Company becoming outstanding. In addition, the Company issued a total of 3,055,554 shares of common stock for $55.0 million in two separate, concurrent private placements upon the closing of the IPO. On November 1, 2017, the Company entered into an underwriting agreement related to a public offering of 6,250,000 shares of the Company’s common stock, par value $0.0001 per share. The offering closed on November 6th and the Company received net proceeds of $141.0 million, after deducting underwriting discounts. Reorganization In July 2014, Intellia Therapeutics, LLC was formed as the parent company of Intellia Therapeutics, Inc. In August 2015, the Company completed a series of transactions pursuant to which Intellia Therapeutics, LLC merged with and into its C corporation subsidiary, Intellia Therapeutics, Inc., with Intellia Therapeutics, Inc. continuing to exist as the surviving corporation (the “Reorganization”). In connection with the Reorganization, all of the outstanding common and preferred unitholders of Intellia Therapeutics, LLC received shares of preferred stock of Intellia Therapeutics, Inc., and holders of incentive units in Intellia Therapeutics, LLC received shares of restricted common stock in Intellia Therapeutics, Inc. The Company determined that the Reorganization lacked economic substance and should be accounted for in a manner consistent with a common control transaction. Similarly, as there was no change in fair value between stockholders, individually or as a class, the Company determined that the exchange of shares occurring in the Reorganization should be accounted for as a modification of the equity securities and presented as a reclassification of the components of equity. The Company classifies stock that is redeemable in circumstances outside of the Company’s control outside of permanent equity. The Company recorded convertible preferred stock at fair value upon issuance, net of any issuance costs or discounts. No accretion was recognized as the contingent events that could give rise to redemption were not deemed probable. The preferred stock outstanding at December 31, 2015 was automatically converted to common stock in connection with the closing of the IPO.

10. Stockholders’ Equity

On May 11, 2016, the Company completed an initial public offering (“IPO”) of its common stock, which resulted in the sale of 6,900,000 shares, including all additional shares available to cover over-allotments, at a price of $18.00 per share. The Company received net proceeds before expenses from the IPO of $115.5 million after deducting underwriting discounts and commissions paid by the Company. In preparation for the IPO, the Company’s board of directors and stockholders approved a one-for-1.7 reverse stock split of the Company’s common stock effective April 25, 2016. All share and per share amounts in the consolidated financial statements and notes thereto have been retroactively adjusted, where necessary, to give effect to this reverse stock split. In connection with the closing of the IPO, all of the Company’s outstanding convertible preferred stock automatically converted to common stock at a one-for-0.6465903 ratio as of May 11, 2016, resulting in an additional 23,481,956 shares of common stock of the Company becoming outstanding. In addition, the Company issued a total of 3,055,554 shares of common stock for $55.0 million in two separate, concurrent private placements upon the closing of the IPO.

On November 1, 2017, the Company entered into an underwriting agreement related to a public offering of 6,250,000 shares of the Company’s common stock, par value $0.0001 per share. The offering closed on November 6th and the Company received net proceeds of $141.0 million, after deducting underwriting discounts.

Reorganization

In July 2014, Intellia Therapeutics, LLC was formed as the parent company of Intellia Therapeutics, Inc. In August 2015, the Company completed a series of transactions pursuant to which Intellia Therapeutics, LLC merged with and into its C corporation subsidiary, Intellia Therapeutics, Inc., with Intellia Therapeutics, Inc. continuing to exist as the surviving corporation (the “Reorganization”). In connection with the Reorganization, all of the outstanding common and preferred unitholders of Intellia Therapeutics, LLC received shares of preferred stock of Intellia Therapeutics, Inc., and holders of incentive units in Intellia Therapeutics, LLC received shares of restricted common stock in Intellia Therapeutics, Inc. The Company determined that the Reorganization lacked economic substance and should be accounted for in a manner consistent with a common control transaction. Similarly, as there was no change in fair value between stockholders, individually or as a class, the Company determined that the exchange of shares occurring in the Reorganization should be accounted for as a modification of the equity securities and presented as a reclassification of the components of equity.

The Company classifies stock that is redeemable in circumstances outside of the Company’s control outside of permanent equity. The Company recorded convertible preferred stock at fair value upon issuance, net of any issuance costs or discounts. No accretion was recognized as the contingent events that could give rise to redemption were not deemed probable. The preferred stock outstanding at December 31, 2015 was automatically converted to common stock in connection with the closing of the IPO.