Equity Plan - Stock Option Activity (Details) - Options - USD ($)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2020
Number of Shares
Outstanding at the beginning of the period (in shares)	2,712,846
Granted (in shares)	329,500
Heritage Commerce Corp stock options	2,627,336	2,627,336
Exercised (in shares)	(320,494)
Forfeited or expired (in shares)	(94,516)
Outstanding at the end of the period (in shares)	2,627,336
Vested or expected to vest (in shares)		2,469,696
Exercisable at the end of the period (in shares)		1,955,675
Weighted Average Exercise Price
Outstanding at the beginning of the period (in dollars per share)	$ 8.80
Granted (in dollars per share)	9.11
Heritage Commerce Corp stock options	9.18	$ 9.18
Exercised (in dollars per share)	4.65
Forfeited or expired (in dollars per share)	13.58
Outstanding at the end of the period (in dollars per share)	$ 9.18
Additional Information
Weighted Average Remaining Contractual Life - Outstanding at the end of the period (in years)	5 years 10 months 6 days
Weighted Average Remaining Contractual Life - Vested or expected to vest (in years)	5 years 10 months 6 days
Weighted Average Remaining Contractual Life - Exercisable at the end of the period (in years)	4 years 9 months 7 days
Aggregate Intrinsic Value - Outstanding at the end of the period (in dollars)		$ 2,403,351
Aggregate Intrinsic Value - Vested or expected to vest (in dollars)		2,259,150
Aggregate Intrinsic Value - Exercisable at the end of the period (in dollars)		$ 2,403,351
Presidio bank
Number of Shares
Heritage Commerce Corp stock options	1,176,757	1,176,757
Outstanding at the end of the period (in shares)	1,176,757