Rigel Pharmaceuticals, Inc. Quarterly report pursuant to Section 13 or 15(d)

Net Loss Per Share (Details) - shares shares in Thousands	3 Months Ended
Net Loss Per Share (Details) - shares shares in Thousands	Mar. 31, 2016	Mar. 31, 2015
Antidilutive securities excluded from the computation of diluted net loss per share
Antidilutive securities excluded from computation of earnings per share (in shares)	22,153	20,356
Employee Stock Option
Antidilutive securities excluded from the computation of diluted net loss per share
Antidilutive securities excluded from computation of earnings per share (in shares)	21,856	20,077
Warrant to purchase common stock
Antidilutive securities excluded from the computation of diluted net loss per share
Antidilutive securities excluded from computation of earnings per share (in shares)	200	200
Employee Stock Purchase Plan
Antidilutive securities excluded from the computation of diluted net loss per share
Antidilutive securities excluded from computation of earnings per share (in shares)	97	79