Shareholders' Equity - Additional Information (Detail) - USD ($)	1 Months Ended			12 Months Ended
	Nov. 30, 2017	Jun. 30, 2017	Aug. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jun. 30, 2008
Shareholders Equity [Line Items]
Preferred stock, shares authorized				2,500,000	2,500,000
Preferred stock, par value				$ 0.001	$ 0.001
Common stock, shares authorized				50,000,000	50,000,000		50,000,000
Common stock, par value				$ 0.001	$ 0.001		$ 0.001
Discount on common stock			$ 2,447,000
Underwriter fees			$ 150,000
Stock Options [Member]
Shareholders Equity [Line Items]
Stock-based compensation plans, number of additional shares authorized for future grants				933,000
Closing price per share of Digimarc common stock				$ 36.15
Vesting period for stock options and restricted stock				3 years
Restricted Stock [Member]
Shareholders Equity [Line Items]
Vesting period for stock options and restricted stock				4 years
Common Stock [Member]
Shareholders Equity [Line Items]
Issuance of common stock	331,000	500,000	1,233,000	831,000	1,418,000	342,000
Common stock price per share	$ 36.25	$ 35.55	$ 30.00
Cash proceeds from sale of common stock	$ 12,000,000	$ 17,775,000	$ 39,953,000
Stock issuance cost	$ 21,000	$ 77,000	$ 253,000
Common Stock [Member] | Stock Incentive Plan [Member]
Shareholders Equity [Line Items]
Authorized shares of Series A Redeemable Nonvoting Preferred stock				3,500,000
Over Allotment Option [Member] | Common Stock [Member]
Shareholders Equity [Line Items]
Issuance of common stock			185,000
Series A Preferred Stock [Member]
Shareholders Equity [Line Items]
Authorized shares of Series A Redeemable Nonvoting Preferred stock				10,000
Series A Preferred redeemable stated fair value				$ 5.00
Series A Preferred stock dividend rights				$ 0
Series A Preferred stock undistributed earnings				$ 0