Share-Based Compensation - Stock option and restricted stock unit activity (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2022	Dec. 31, 2021
Amount, Outstanding	2,501,419
Amount, Granted	427,390
Amount, Outstanding	1,888,622	2,501,419
Weighted-average exercise price, Outstanding	$ 4.35
Weighted-average exercise price, Granted	8.88
Weighted-average exercise price, Outstanding	$ 3.58	$ 4.35
Biostage2013 Equity Incentive Plan [Member] | Stock Options [Member]
Amount, Outstanding	2,332,603
Amount, Granted	189,828
Amount, Canceled / forfeited	(50,097)
Amount, Outstanding	2,472,334	2,332,603
Amount, Options exercisable	1,197,964
Amount, Options vested and expected to vest	2,387,217
Weighted-average exercise price, Outstanding	$ 3.93
Weighted-average exercise price, Granted	4.67
Weighted-average exercise price, Canceled / forfeited	2.70
Weighted-average exercise price, Outstanding	3.88	$ 3.93
Weighted-average exercise price, Options exercisable	5.19
Weighted-average exercise price, Options vested and expected to vest	$ 3.92
Weighted-average contractual life, Outstanding	8 years 1 month 9 days	8 years 3 months 18 days
Weighted-average contractual life, Options exercisable	7 years 7 months 20 days
Outstanding at the beginning (in dollars)	$ 129
Outstanding at the end (in dollars)	4,966	$ 129
Exercisable at the end (in dollars)	$ 2,419