Revenue Recognition (Details) $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Apr. 30, 2016	Mar. 31, 2018 USD ($) item	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)
Agreement term	4 years
Total revenues		$ 62,340	$ 49,382	$ 49,382
Noncurrent deferred revenue		35,462
Deferred revenue, current portion		1,443		1,420
Product
Revenue recognized		900
Total revenues		$ 54,269	48,394	48,394
Product | Minimum
Performance obligation, expected timing		9 months
Product | Maximum
Performance obligation, expected timing		12 months
Licensing and other
Total revenues		$ 8,071	$ 988	$ 988
Evercord
Deferred revenue		$ 2,400
Evercord | Processing and storage services
Number of performance obligations | item		2
Evercord | Processing and storage services | Minimum
Performance obligation, expected timing		6 months
Evercord | Processing and storage services | Maximum
Performance obligation, expected timing		18 months
Qiagen
Revenue recognized		$ 5,500
Qiagen | The Qiagen Agreement
Agreement term		10 years
Initial transaction price		$ 15,000
Qiagen | Estimated recognition through 2022
Deferred revenue, noncurrent		$ 9,500
Laboratory distribution partners | Product | Minimum
Performance obligation, expected timing		2 months
Laboratory distribution partners | Product | Maximum
Performance obligation, expected timing		3 months