Represents the information pertaining to additional offering price.

No definition available.

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Namespace Prefix:	bcyc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the information pertaining to aggregate offering price.

+ References

No definition available.

+ Details

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Namespace Prefix:	bcyc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash inflow from the additional capital contribution to the entity.

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- Definition

Per share or per unit amount of equity securities issued.

+ References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Number of new stock issued during the period.

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Period Type:	duration

- Definition

Equity impact of the value of new stock issued during the period. Includes shares issued in an initial public offering or a secondary public offering.

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- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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Subsequent events (Details) - USD ($) $ / shares in Units, $ in Thousands				3 Months Ended		9 Months Ended
	Oct. 02, 2020	Oct. 01, 2020	Jun. 05, 2020	Sep. 30, 2020	Jun. 30, 2019	Sep. 30, 2020
Subsequent events
Stock Issued During Period, Value, New Issues				$ 46,323	$ 56,528
Sales Agreement \| Subsequent events
Subsequent events
Maximum Additional Offering Price	$ 75,000
Hercules
Subsequent events
Stock Issued During Period, Value, New Issues						$ 2,000
Hercules \| Sales Agreement \| Subsequent events
Subsequent events
Stock Issued During Period, Value, New Issues		$ 50,000
At the market offering
Subsequent events
Maximum aggregate offering price			$ 50,000
Shares issued (in shares)						2,830,713
Net proceeds						$ 46,300
At the market offering \| Hercules \| Sales Agreement \| Subsequent events
Subsequent events
Shares issued (in shares)		98,100
Share issue price		$ 19.05
Net proceeds		$ 1,800