X0306 4 2019-08-06 false 0001656328 Sienna Biopharmaceuticals, Inc. SNNA 0001573074 Beddingfield III Frederick C/O SIENNA BIOPHARMACEUTICALS, INC. 30699 RUSSELL RANCH ROAD, SUITE 140 WESTLAKE VILLAGE CA 91362 true true false false President & CEO Common Stock 2019-08-06 4 A false 150000.00 A 967599.00 D Common Stock 112614.00 I See Footnote Stock Options (Right to buy) 15.08 2019-08-06 4 D false 190910.00 D 2028-06-01 Common Stock 190910.00 0.00 D Stock Options (Right to buy) 15.00 2019-08-06 4 D false 42590.00 D 2027-07-26 Common Stock 42590.00 0.00 D Stock Options (Right to buy) 2.32 2019-08-06 4 D false 40968.00 D 2019-01-01 2029-01-01 Common Stock 40968.00 0.00 D Stock Options (Right to buy) 2.32 2019-08-06 4 D false 93750.00 D 2029-01-01 Common Stock 93750.00 0.00 D Stock Options (Right to buy) 2.32 2019-08-06 4 D false 93750.00 D 2029-01-01 Common Stock 93750.00 0.00 D Stock Options (Right to buy) 0.71 2019-08-06 4 A false 42590.00 A 2027-07-26 Common Stock 42590.00 42590.00 D Stock Options (Right to buy) 0.71 2019-08-06 4 A false 190910.00 A 2028-06-01 Common Stock 190910.00 190910.00 D Stock Options (Right to buy) 0.71 2019-08-06 4 A false 40968.00 A 2019-01-01 2029-01-01 Common Stock 40968.00 40968.00 D Stock Options (Right to buy) 0.71 2019-08-06 4 A false 93750.00 A 2029-01-01 Common Stock 93750.00 93750.00 D Stock Options (Right to buy) 0.71 2019-08-06 4 A false 93750.00 A 2029-01-01 Common Stock 93750.00 93750.00 D Award of restricted stock units ("RSUs") granted under the Issuer's 2017 Incentive Award Plan. Each RSU entitles the Reporting Person to receive one share of Issuer common stock upon vesting. The award vests as to fifty percent (50%) of the total number of RSUs on February 6, 2020, twenty-five percent (25%) of the total number of RSUs on August 6, 2020, and the remaining twenty-five percent (25%) of the total number of RSUs on February 6, 2021, in each case, subject to the Reporting Person's continued employment or service relationship with the Issuer through the applicable vesting date. Includes a total of 5,916 shares of the Issuer's common stock acquired pursuant to the Issuer's Employee Stock Purchase Plan. The shares are directly held by the Beddingfield Family Trust. The transaction reported herein reflect a one-time stock option repricing (the "Option Repricing") that became effective on August 6, 2019 and are being reported in this manner solely to comply with the technical reporting requirements under Section 16(a) of the Securities Exchange Act of 1934. Pursuant to the Option Repricing, the exercise price of each relevant option has been amended to reduce such exercise price to $0.71. There have been no other changes to the terms of the relevant options. Twenty-Five percent (25%) of the shares subject to the option vest and become exercisable on the first anniversary measured from June 1, 2018, and the remaining shares subject to the option vest and become exercisable in 36 successive, equal monthly installments thereafter, subject to the Reporting Person's continued employment or service relationship with the Issuer on each such vesting date. Twenty-Five percent (25%) of the share subject to the option vest and become exercisable on the first anniversary measured from July 26, 2017, and the remaining shares subject to the option vest and become exercisable in 36 successive, equal monthly installments thereafter, subject to the Reporting Person's continued employment or service relationship with the Issuer on each such vesting date. Twenty percent (20%) of the shares subject to the option vest and become exercisable upon satisfaction of one performance-based milestone, forty percent (40%) of the shares vest and become exercisable upon satisfaction of a second performance-based milestone, and the remaining forty percent (40%) of the shares vest and become exercisable upon satisfaction of a third performance-based milestone, subject to the Reporting Person's continued employment or service relationship with the Issuer on each such vesting date. Twenty-five percent (25%) of the shares subject to the option vest and become exercisable on July 1,2019, twenty-five percent (25%) of the shares vest and become exercisable on January 1, 2020, and the remaining shares vest and become exercisable in 12 successive, equal monthly installments thereafter, subject to the Reporting Person's continued employment or service relationship with the Issuer on each such vesting date. /s/ Timothy K. Andrews, attorney-in-fact for Frederick C. Beddingfield III 2019-08-08