Net Income Attributable to Penumbra, Inc. Per Share - Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Numerator:
Net (loss) income attributable to Penumbra, Inc.	$ (11,960)	$ 16,588	$ (10,535)	$ 27,286
Weighted average shares used to compute net income attributable to common stockholders:
Basic (in shares)	35,400,542	34,694,228	35,221,727	34,601,270
Potential dilutive stock-based options and awards (in shares)	0	1,520,093	0	1,613,092
Diluted (in shares)	35,400,542	36,214,321	35,221,727	36,214,362
Net (loss) income attributable to Penumbra, Inc. per share:
Basic (in dollars per share)	$ (0.34)	$ 0.48	$ (0.30)	$ 0.79
Diluted (in dollars per share)	$ (0.34)	$ 0.46	$ (0.30)	$ 0.75