I'm Sergei Tokmakov, California attorney (Bar #279869). The prior comments are right that one-way NDAs are common from sophisticated investors, but here's what to actually watch for in the doc:
(1) Definition of confidential information — should exclude info already public, independently developed, or learned from third parties. (2) Term of confidentiality — 2 years standard, 5 years acceptable, longer is a flag. (3) Permitted disclosures — internal team, advisors, lawyers, accountants on need-to-know. (4) Residuals clause — many investor NDAs include a residuals clause letting them use anything remembered without notes; in early-stage SaaS this is usually fine but read it. (5) No non-solicitation clause — should not bind you to anything beyond confidentiality.
If the term is over 5 years, residuals is overbroad, or there's any non-compete language, push back politely. Most legitimate investors will redline. Informational only.